Re: I am out of trial and error again Lists
On 22/10/2014 21:30, Seymore4Head wrote: def nametonumber(name): lst=[""] for x,y in enumerate (name): lst=lst.append(y) print (lst) return (lst) a=["1-800-getcharter"] print (nametonumber(a))#18004382427837 The syntax for when to use a () and when to use [] still throws me a curve. For now, I am trying to end up with a list that has each character in "a" as a single item. I get: None None Following on from the numerous responses you've had here, I've no idea if this helps your thought processes but there's only one way for you to find out http://www.greenteapress.com/thinkpython/ :) -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: When to use assert
Dan Stromberg wrote:
> I like to use assertions and "if cond: raise ValueError('foo')" a lot.
>
> I think Eiffel may be the poster-child for a language with
> pre-conditions, post-conditions and assertions.
Yes. I don't think Eiffel is the only language with explicit support for
testing invariants, but it's probably the best known one.
https://archive.eiffel.com/doc/online/eiffel50/intro/language/invitation-07.html
Others include Ada2012, Mercury, D, Perl6, Cobra, Clojure, and others. Cobra
is especially interesting as the syntax is heavily influenced by Python's.
http://cobra-language.com/trac/cobra/wiki/Contracts
> I think you're in good company - a lot of developers don't use assertions
> much.
"You" in this context is Chris Angelico.
> I like assertions, because they tend to stop bugs pretty quickly. If
> you have 3 functions, one calling another calling another, assertions
> in each can keep you from having to backtrack among them when
> debugging, instead going directly to the problem's source.
Yes, the purpose of assertions is to help errors be discovered as close to
the cause as possible, rather than somewhere much later on. Consider:
addresses = [get_address(name) for name in database]
# ... much later on ...
for i, address in enumerate(addresses):
if some_condition():
addresses[i] = modify(address)
# ... much later on ...
for address in list_of_addresses:
process_non_empty_address(address)
where you can't easily modify or check the get_address() and modify()
functions. If you have a failure in process_non_empty_address, due to a
violation of the "address must not be empty" invariant, which function is
to blame?
You could wrap them and find out that way:
from somewhere import get_address as _get_addr
def get_address(*args, **kwargs):
result = _get_addr(*args, **kwargs)
if not result:
raise RuntimeError("bug in get_address")
return result
and under some circumstances that's a good strategy, but often you just want
to determine which function is violating the constraint, fix that one, and
leave the other unmodified.
addresses = [get_address(name) for name in database]
assert all(address for address in addresses)
# ... much later on ...
for i, address in enumerate(addresses):
if some_condition():
addresses[i] = modify(address)
assert addresses[i]
will either identify the culprit, or at least prove that neither
get_address() nor modify() are to blame. Because you're using an assertion,
it's easy to leave the asserts in place forever, and disable them by
passing -O to the Python interpreter in production.
[Aside: it would be nice if Python did it the other way around, and require
a --debugging switch to turn assertions on. Oh well.]
>> This is the job of a test suite.
>
> Test suites are great, and I can't really question your reliance on
> them. I love having lots of automated tests. But for the reason I
> described above, I still like having lots of assertions.
Assertions and test suites are complementary, not in opposition, like belt
and braces. Assertions insure that the code branch will be tested if it is
ever exercised, something test suites can't in general promise. Here's a
toy example:
def some_function(value):
import random
random.seed(value)
if random.random() == 0.25000375:
assert some_condition
else:
pass
Try writing a unit test that guarantees to test the some_condition
branch :-)
[Actually, it's not that hard, if you're willing to monkey-patch the random
module. But you may have reasons for wanting to avoid such drastic
measures.]
I don't know what value will cause some_function() to take the
some_condition branch, but I know that if it ever takes that branch, the
assert will guard it, regardless of whether or not I've written a unit test
to cover that situation.
>> You don't pepper your code with
>> assertions to the effect that "I just pushed something onto my queue,
>> it should now have this item in it"; you create a test case for it,
>> and verify your function there. In the rest of the code, you trust
>> that your test suite passes, and don't waste time with assertions.
>
> I wouldn't test that a value was added to a queue immediately after
> adding it. That's excessive, and may even require an abstraction
> violation.
>
> But if, for example, I have a string with 3 known-good values, I'll
> if/elif/elif/else, and make the else raise an AssertionError. The
> assertion should never fire, but if the code changes, it could, and if
> there's a typo somewhere, it could then too.
I like this style:
assert x in (a, b, c)
if x == a:
do_this()
elif x == b:
do_that()
else:
assert x == c
do_something_else()
Why do I prefer that? To defend against future code changes. Defensive
programming can defend not only against bugs in the current code, but also
bugs in *future* code. Consider this common case:
# x is either a or b.
if x == a:
do_this()
ANN: eGenix pyOpenSSL Distribution 0.13.5
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Re: I am out of trial and error again Lists
On 24/10/2014 08:05, Mark Lawrence wrote: On 22/10/2014 21:30, Seymore4Head wrote: def nametonumber(name): lst=[""] for x,y in enumerate (name): lst=lst.append(y) print (lst) return (lst) a=["1-800-getcharter"] print (nametonumber(a))#18004382427837 The syntax for when to use a () and when to use [] still throws me a curve. For now, I am trying to end up with a list that has each character in "a" as a single item. I get: None None Following on from the numerous responses you've had here, I've no idea if this helps your thought processes but there's only one way for you to find out http://www.greenteapress.com/thinkpython/ :) And another http://tinyurl.com/k26vjhr -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: When to use assert
On Fri, Oct 24, 2014 at 6:49 PM, Steven D'Aprano
wrote:
> addresses = [get_address(name) for name in database]
> assert all(address for address in addresses)
> # ... much later on ...
> for i, address in enumerate(addresses):
> if some_condition():
> addresses[i] = modify(address)
> assert addresses[i]
>
>
> will either identify the culprit, or at least prove that neither
> get_address() nor modify() are to blame. Because you're using an assertion,
> it's easy to leave the asserts in place forever, and disable them by
> passing -O to the Python interpreter in production.
The first assertion is fine, assuming that the emptiness of your
address corresponds to falsiness as defined in Python. (This could be
safe to assume, if the address is an object that knows how to boolify
itself.) The second assertion then proves that modify() isn't
returning nothing, but that might be better done by sticking the
assertion into modify itself.
And that's what I'm talking about: checking a function's postcondition
with an assert implies putting that assertion after every call, and
anything that you have to do every time you call a function belongs
inside that function. Imagine writing this kind of defensive code, and
then having lots of places that call modify()... and missing the
assert in some of them. Can you trust what you're getting back?
> [Aside: it would be nice if Python did it the other way around, and require
> a --debugging switch to turn assertions on. Oh well.]
Maybe. But unless someone actually tests that their assertions are
being run, there's the risk that they're flying blind and assuming
that it's all happening. There'll be all these lovely "checked
comments"... or so people think. Nobody ever runs the app with
--debugging, so nobody ever sees anything.
> Assertions and test suites are complementary, not in opposition, like belt
> and braces. Assertions insure that the code branch will be tested if it is
> ever exercised, something test suites can't in general promise. Here's a
> toy example:
>
> def some_function(value):
> import random
> random.seed(value)
> if random.random() == 0.25000375:
> assert some_condition
> else:
> pass
>
>
> Try writing a unit test that guarantees to test the some_condition
> branch :-)
>
> [Actually, it's not that hard, if you're willing to monkey-patch the random
> module. But you may have reasons for wanting to avoid such drastic
> measures.]
Easy. You craft a test case that passes the right argument, and then
have the test case test itself. You will want to have a script that
figures out what seed value to use:
def find_seed(value):
import random
for seed in range(100): # Restrict to not-too-many tries
random.seed(seed)
if random.random() == value: return seed
I didn't say it'd be efficient to run, but hey, it's easy. I've no
idea how many bits of internal state the default Python RNGs use, but
testing a million seeds took a notable amount of time, so I told it to
fail after that many. (And I didn't find one that gave that result.)
But actually, it would be really simple to monkey-patch. And in any
non-toy situation, there's probably something more significant being
tested here... unless you really are probing a random number generator
or something, in which case you probably know more about its
internals.
> I like this style:
>
> assert x in (a, b, c)
> if x == a:
> do_this()
> elif x == b:
> do_that()
> else:
> assert x == c
> do_something_else()
If all your branches are simple function calls, I'd be happy with a
KeyError instead of an AssertionError or RuntimeError.
{a:do_this, b:do_that, c:do_something_else}[x]()
I was talking to a student this week who had a long if/elif chain that
translated keywords into values, something like this:
def get_whatever_value(kwd):
if kwd == 'value_should_be_50':
return 50
elif kwd == 'value_wants_to_be_75':
return 75
elif kwd == 'one_hundred':
return 100
There was no 'else' clause, so in the event of an incorrect keyword,
it would return None. Now, I could have advised adding an "else
ValueError" or an assertion, but my preferred technique here is a
simple dict lookup. Simpler AND guarantees that all inputs are
checked.
>>> Or is that insufficiently paranoid?
>>
>> With good tests, you're probably fine.
>
> Is it possible to be too paranoid when it comes to tests?
Yeah, it is. I said earlier about checking that len() returns an
integer. The only way[1] for len(some_object) to return a non-integer
is for someone to have shadowed len, and if you're asserting to see if
someone's maliciously shadowing builtins, you *really* need a hobby.
But hey. Maybe asserting *is* your hobby!
ChrisA
[1] Cue the response pointing out some way that it'll return something
else. I wasn't able to break it, though.
--
https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
Marko Rauhamaa wrote:
> "BartC" :
>
>>> Ah, but what would
>>>
>>> x = [f, g][cond]()
>>>
>>> produce?
>>
>> It will select f or g (which should refer to functions), and call one of
>> those depending on cond. That's not a problem.
>>
>> The problem is it will still evaluate both f and g,
>
> That's not really the problem. The problem is in readability.
I don't get why that's considered hard to read. We write things like this
all the time:
item = somelist[index]
value = data[key]
Presumably people won't have a problem with:
values = [f(), g(), h()]
value = values[index]
(If they do, they're going to have a bad time with Python.) They probably
won't even mind if we skip the temporary variable:
value = [f(), g(), h()][index]
and if they're experienced with languages that treat functions as
first-class values, they'll be fine with factoring out the function call:
value = [f, g, h][index]()
So why is it hard to read when the index is a flag?
value = [f, g][cond]()
Of course one can write hard-to-read code using any idiom by sheer weight of
complexity or obfuscated naming:
value = [some_function(arg)[23]['key'] or
another_function.method((x + y)/(z-x**(y-4)))*
some_list[get_index(a)].spam(eggs=False, tomato='yum'),
something.do_this(p|q).get(alpha, beta) ^
aardvark.bobble("string%s" % carrot.gamma(r&s)*
(this & that).fetch(83, 36, when=when or "now")
][cond or flag or foo(42)-1 > 17 or bar(b) < thingy(c) or not d]
but re-writing that using ternary if operator won't help one iota. I don't
see why `[a, b][flag]` is inherently less readable than `b if flag else a`.
--
Steven
--
https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
On Fri, Oct 24, 2014 at 7:38 PM, Steven D'Aprano
wrote:
> Of course one can write hard-to-read code using any idiom by sheer weight of
> complexity or obfuscated naming:
>
> value = [some_function(arg)[23]['key'] or
> another_function.method((x + y)/(z-x**(y-4)))*
> some_list[get_index(a)].spam(eggs=False, tomato='yum'),
> something.do_this(p|q).get(alpha, beta) ^
> aardvark.bobble("string%s" % carrot.gamma(r&s)*
> (this & that).fetch(83, 36, when=when or "now")
> ][cond or flag or foo(42)-1 > 17 or bar(b) < thingy(c) or not d]
>
I can see where your problem is. It is a cardinal error in readability
to have "(x + y)" followed by "z-x". No wonder it's hard to read.
ChrisA
--
https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
Steven D'Aprano : > So why is it hard to read when the index is a flag? > > value = [f, g][cond]() So, subjectively, which syntax would you prefer: if j < 10: j += 1 else: j = 3 or: j = j + 1 if j < 10 else 3 or: j = (lambda: 3, lambda: j + 1)[j < 10]() Marko -- https://mail.python.org/mailman/listinfo/python-list
Re: setuptools + data_files = 2
On 2014-10-23, Simon Kennedy wrote:
> If you're creating an sdist then you'll need to create a MANIFEST.in
> file in the same folder as setup.py with the following contents
>
> include share/test_file.txt
>
> If you're creating a bdist (egg or wheel) the parameter name you need
> is
>
> package_data={'share': [share/test_file.txt]},
thanks man.
--
https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
Marko Rauhamaa wrote: > Steven D'Aprano : > >> So why is it hard to read when the index is a flag? >> >> value = [f, g][cond]() > > So, subjectively, which syntax would you prefer: Depends on what else the code is doing. But my personal preference is a red herring: you didn't say that you "liked" or "preferred" one version over the other, you said that the problem with the [f, g][cond] idiom is readability, implying that it is hard to read. I'm not asking for your personal preference, I'm asking for justification for your suggestion that it is hard to read. > if j < 10: > j += 1 > else: > j = 3 > > or: > > j = j + 1 if j < 10 else 3 > > or: > > j = (lambda: 3, lambda: j + 1)[j < 10]() Certainly not the third one. That's needlessly obfuscated for the sake of premature optimization. This version is much better, and probably not only simpler and easier to read but probably more efficient too: j = (3, j + 1)[j < 10] -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Thu, 23 Oct 2014 21:56:31 -0700 (PDT), Rustom Mody wrote: >On Thursday, October 23, 2014 10:33:57 PM UTC+5:30, Seymore4Head wrote: >> On Thu, 23 Oct 2014 15:55:35 + (UTC), Denis McMahon wrote: >> >> >On Thu, 23 Oct 2014 10:04:56 -0400, Seymore4Head wrote: >> > >> >> On Thu, 23 Oct 2014 09:15:16 + (UTC), Denis McMahon wrote: >> > >> >>>Try the following 3 commands at the console: >> > >> >You obviously didn't, so I'll try again. Try each of the following three >> >commands in the python console at the ">>>" prompt. >> > >> >1) 10 >> 10 >> >> >2) range(10) >> range(0, 10) >> >> >3) str(range(10)) >> 'range(0, 10)' >> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >> > >> >Show *and* describe the output in each case. Describing the output that >> >you see is actually the key here, as it will allow us to assess whether >> >you understand what you are actually seeing or not, and if you don't >> >understand the output you see in the console, then we need to fix that >> >very fundamental and basic issue before moving on to more complex stuff! >> > >> >> Ok Thanks >> > >> >You were expected to answer the question in the original. I have now set >> >it as a clearer and more specific task. >> > >> >If you're not going to do these things that are intended to help you >> >learn some of the basic features of the language, then I and everyone >> >else here that has so far been attempting to help you are wasting our >> >time. >> >> I did try them. I may have missed replying your to your specific >> comment, but I tried them. >> >> BTW str(range (10)) does work with Python 2 which is where I may have >> got the idea. I happened to be using Python 3 at the time I tried to >> implement it. It is a little confusing jumping back and forth, but >> for the moment, I am going to tough it out. >> >> I do appreciate all the help too. > >Hi Seymore! > >Happy to see that you are moving on from >"reading much; understanding nothing; thrashing" > >to > >"reading a bit; understanding a bit" >[And thanks to Denis to getting you out of your confusion-hole] > >So heres a small additional question set that I promise will more than repay >you your time. > >Better done in python 2. But if you use python3, below replace >range(10) >with >list(range(10)) > >So now in the python console, please try > >a. range(10) > >and > >b. print (range(10)) > >And then post back (without consulting google!!)¹ > >1. Are they same or different? > >2. If same, how come different expressions are same? > >3. If different whats the difference? > >4. [Most important]: When would you prefer which? > >= >¹ Actually its ok to consult google AFTER you try I do get the difference. I don't actually use Python 2. I use CodeSkulptor. I do have Python 3 installed. Actually I have Python 2 installed but IDLE defaults to Python 3. So it is a pain to actually load Python 2. Range(10) stores the min max values and loads each number in between when needed. Ian explained that very clearly. I tried list(range(10) I thought that would work in Python 3. It didn't. I spent quite a bit of time last night trying to come up with the right combination of str and int commands to make range(10) work with my simple example. It didn't. I am pretty frustrated. I am just skipping that little bit of code for the moment. Thanks everyone for your suggestions. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 08:05:01 +0100, Mark Lawrence wrote: >On 22/10/2014 21:30, Seymore4Head wrote: >> def nametonumber(name): >> lst=[""] >> for x,y in enumerate (name): >> lst=lst.append(y) >> print (lst) >> return (lst) >> a=["1-800-getcharter"] >> print (nametonumber(a))#18004382427837 >> >> >> The syntax for when to use a () and when to use [] still throws me a >> curve. >> >> For now, I am trying to end up with a list that has each character in >> "a" as a single item. >> >> I get: >> None >> None >> > >Following on from the numerous responses you've had here, I've no idea >if this helps your thought processes but there's only one way for you to >find out http://www.greenteapress.com/thinkpython/ :) I have at least 10 ebooks. I will get around to reading them soon. http://i.imgur.com/rpOcKP8.jpg Thanks -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, Oct 25, 2014 at 1:38 AM, Seymore4Head wrote: > I tried list(range(10) I thought that would work in Python 3. It > didn't. This is your problem: You say "it didn't work". That is almost *never* the right thing to say or to think. What happened when you tried that? Did you get a SyntaxError because of the omitted close parenthesis? Did the interpreter prompt for more input? Did a velociraptor come out of nowhere and try to kill you [1]? When you come back to python-list, you should say exactly what you did and exactly what happened, not "I tried X and it didn't work". Copy and paste from your interactive session - do NOT retype, because you introduce new errors. It's very hard to help you when you don't explain what you're doing, and just keep on telling us how frustrated you are. ChrisA [1] http://xkcd.com/292/ -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 09:12:28 +0100, Mark Lawrence wrote: >On 24/10/2014 08:05, Mark Lawrence wrote: >> On 22/10/2014 21:30, Seymore4Head wrote: >>> def nametonumber(name): >>> lst=[""] >>> for x,y in enumerate (name): >>> lst=lst.append(y) >>> print (lst) >>> return (lst) >>> a=["1-800-getcharter"] >>> print (nametonumber(a))#18004382427837 >>> >>> >>> The syntax for when to use a () and when to use [] still throws me a >>> curve. >>> >>> For now, I am trying to end up with a list that has each character in >>> "a" as a single item. >>> >>> I get: >>> None >>> None >>> >> >> Following on from the numerous responses you've had here, I've no idea >> if this helps your thought processes but there's only one way for you to >> find out http://www.greenteapress.com/thinkpython/ :) >> > >And another http://tinyurl.com/k26vjhr Google. I have heard of that. :) -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, 25 Oct 2014 01:51:41 +1100, Chris Angelico wrote: >On Sat, Oct 25, 2014 at 1:38 AM, Seymore4Head > wrote: >> I tried list(range(10) I thought that would work in Python 3. It >> didn't. > >This is your problem: You say "it didn't work". That is almost *never* >the right thing to say or to think. What happened when you tried that? >Did you get a SyntaxError because of the omitted close parenthesis? >Did the interpreter prompt for more input? Did a velociraptor come out >of nowhere and try to kill you [1]? > I understand that it makes it easier for you if I can describe better the error I get, but by the time I ask for help here I have tried many different things to get the error to go away. I will try in the future to do better at this. For now, I am just putting that exercise behind me. I do try to find out how to do things before asking first. I tried so many things last night, I had to go back to an old message to get code that worked again. Thanks >When you come back to python-list, you should say exactly what you did >and exactly what happened, not "I tried X and it didn't work". Copy >and paste from your interactive session - do NOT retype, because you >introduce new errors. It's very hard to help you when you don't >explain what you're doing, and just keep on telling us how frustrated >you are. > >ChrisA > >[1] http://xkcd.com/292/ -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, Oct 25, 2014 at 2:04 AM, Seymore4Head wrote: > I understand that it makes it easier for you if I can describe better > the error I get, but by the time I ask for help here I have tried many > different things to get the error to go away. That's part of the problem. You let yourself get frustrated and confused, and you still have no idea what you're doing. Ask sooner, if you have to; or develop the discipline to keep track of what you do and what happens. But regardless of what actually happens, "it didn't work" is not a helpful thing to say. Trust me, making it easier for us will make everything easier for you too. Even if we were to never answer a single question of yours ever again, learning to read error messages will benefit you more than you can imagine. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 8:11:12 PM UTC+5:30, Seymore4Head wrote: > On Thu, 23 Oct 2014 21:56:31 -0700 (PDT), Rustom Mody wrote: > > >On Thursday, October 23, 2014 10:33:57 PM UTC+5:30, Seymore4Head wrote: > >> On Thu, 23 Oct 2014 15:55:35 + (UTC), Denis McMahon wrote: > >> > >> >On Thu, 23 Oct 2014 10:04:56 -0400, Seymore4Head wrote: > >> > > >> >> On Thu, 23 Oct 2014 09:15:16 + (UTC), Denis McMahon wrote: > >> > > >> >>>Try the following 3 commands at the console: > >> > > >> >You obviously didn't, so I'll try again. Try each of the following three > >> >commands in the python console at the ">>>" prompt. > >> > > >> >1) 10 > >> 10 > >> > >> >2) range(10) > >> range(0, 10) > >> > >> >3) str(range(10)) > >> 'range(0, 10)' > >> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] > >> > > >> >Show *and* describe the output in each case. Describing the output that > >> >you see is actually the key here, as it will allow us to assess whether > >> >you understand what you are actually seeing or not, and if you don't > >> >understand the output you see in the console, then we need to fix that > >> >very fundamental and basic issue before moving on to more complex stuff! > >> > > >> >> Ok Thanks > >> > > >> >You were expected to answer the question in the original. I have now set > >> >it as a clearer and more specific task. > >> > > >> >If you're not going to do these things that are intended to help you > >> >learn some of the basic features of the language, then I and everyone > >> >else here that has so far been attempting to help you are wasting our > >> >time. > >> > >> I did try them. I may have missed replying your to your specific > >> comment, but I tried them. > >> > >> BTW str(range (10)) does work with Python 2 which is where I may have > >> got the idea. I happened to be using Python 3 at the time I tried to > >> implement it. It is a little confusing jumping back and forth, but > >> for the moment, I am going to tough it out. > >> > >> I do appreciate all the help too. > > > >Hi Seymore! > > > >Happy to see that you are moving on from > >"reading much; understanding nothing; thrashing" > > > >to > > > >"reading a bit; understanding a bit" > >[And thanks to Denis to getting you out of your confusion-hole] > > > >So heres a small additional question set that I promise will more than repay > >you your time. > > > >Better done in python 2. But if you use python3, below replace > >range(10) > >with > >list(range(10)) > > I tried list(range(10) I thought that would work in Python 3. It > didn't. I spent quite a bit of time last night trying to come up with > the right combination of str and int commands to make range(10) work > with my simple example. It didn't. I am pretty frustrated. I am > just skipping that little bit of code for the moment. I asked you to try list(range(10)) Did you try EXACTLY (cut-paste) that? You are claiming to have tried list(range(10) Thats one closing parenthesis less The interaction with your version would go something like this: [Two versions The KeyboardInterrupt comes from giving a control-C Dunno what happens in codeskulptor ] >>> list(range(10) ... ... ... ... ) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> list(range(10) ... KeyboardInterrupt > > Thanks everyone for your suggestions. 1. You are reading too much 2. Trying to hard Think of riding a bicycle. Cant do it by reading many books on cycling -- thats 1. Nor by holding the handle so hard you tremble -- thats 2. Just relax a bit... And take small steps Chill... as Chris joked, no monster in the computer (or on this list!) > Range(10) stores the min max values and loads each number in between > when needed. It loads?? As in 'load-up-a-van'?? When you see: >>> 10 10 1. Does someone (a clerk maybe) in the computer count to 10? 2. Or do you, seeing that interaction, count to 10? [If you do, replace the 10 by 1000] 3. Or do you, remember what it means to count to 10 without having to do it? Now go back to your statement about 'loading' and find a better verb -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
ERRATA CORRIGE: > many different circumstances, by the very, very helpful folks of clp. many different circumstances, by the very, very helpful folks of clpy -- sapete contare fino a venticinque? Olimpia Milano Jugoplastika Split Partizan Beograd Roberto Premier Duska Ivanovic Zarko Paspalj -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, Oct 24, 2014 at 9:56 AM, Rustom Mody wrote: >> Range(10) stores the min max values and loads each number in between >> when needed. > > It loads?? As in 'load-up-a-van'?? As in loads into memory. > When you see: > 10 > 10 > > 1. Does someone (a clerk maybe) in the computer count to 10? > 2. Or do you, seeing that interaction, count to 10? >[If you do, replace the 10 by 1000] > 3. Or do you, remember what it means to count to 10 without having to do it? I don't understand why you think any of these are implied by the word "load". > Now go back to your statement about 'loading' and find a better verb I presume he used "load" because that was the word I used in my explanatory post about the difference between range in Python 2 and Python 3 yesterday. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 08:56:31 -0700 (PDT), Rustom Mody wrote: >On Friday, October 24, 2014 8:11:12 PM UTC+5:30, Seymore4Head wrote: >> On Thu, 23 Oct 2014 21:56:31 -0700 (PDT), Rustom Mody wrote: >> >> >On Thursday, October 23, 2014 10:33:57 PM UTC+5:30, Seymore4Head wrote: >> >> On Thu, 23 Oct 2014 15:55:35 + (UTC), Denis McMahon wrote: >> >> >> >> >On Thu, 23 Oct 2014 10:04:56 -0400, Seymore4Head wrote: >> >> > >> >> >> On Thu, 23 Oct 2014 09:15:16 + (UTC), Denis McMahon wrote: >> >> > >> >> >>>Try the following 3 commands at the console: >> >> > >> >> >You obviously didn't, so I'll try again. Try each of the following three >> >> >commands in the python console at the ">>>" prompt. >> >> > >> >> >1) 10 >> >> 10 >> >> >> >> >2) range(10) >> >> range(0, 10) >> >> >> >> >3) str(range(10)) >> >> 'range(0, 10)' >> >> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >> >> > >> >> >Show *and* describe the output in each case. Describing the output that >> >> >you see is actually the key here, as it will allow us to assess whether >> >> >you understand what you are actually seeing or not, and if you don't >> >> >understand the output you see in the console, then we need to fix that >> >> >very fundamental and basic issue before moving on to more complex stuff! >> >> > >> >> >> Ok Thanks >> >> > >> >> >You were expected to answer the question in the original. I have now set >> >> >it as a clearer and more specific task. >> >> > >> >> >If you're not going to do these things that are intended to help you >> >> >learn some of the basic features of the language, then I and everyone >> >> >else here that has so far been attempting to help you are wasting our >> >> >time. >> >> >> >> I did try them. I may have missed replying your to your specific >> >> comment, but I tried them. >> >> >> >> BTW str(range (10)) does work with Python 2 which is where I may have >> >> got the idea. I happened to be using Python 3 at the time I tried to >> >> implement it. It is a little confusing jumping back and forth, but >> >> for the moment, I am going to tough it out. >> >> >> >> I do appreciate all the help too. >> > >> >Hi Seymore! >> > >> >Happy to see that you are moving on from >> >"reading much; understanding nothing; thrashing" >> > >> >to >> > >> >"reading a bit; understanding a bit" >> >[And thanks to Denis to getting you out of your confusion-hole] >> > >> >So heres a small additional question set that I promise will more than repay >> >you your time. >> > >> >Better done in python 2. But if you use python3, below replace >> >range(10) >> >with >> >list(range(10)) > > > >> >> I tried list(range(10) I thought that would work in Python 3. It >> didn't. I spent quite a bit of time last night trying to come up with >> the right combination of str and int commands to make range(10) work >> with my simple example. It didn't. I am pretty frustrated. I am >> just skipping that little bit of code for the moment. > >I asked you to try >list(range(10)) > >Did you try EXACTLY (cut-paste) that? > >You are claiming to have tried >list(range(10) > >Thats one closing parenthesis less > >The interaction with your version would go something like this: >[Two versions >The KeyboardInterrupt comes from giving a control-C >Dunno what happens in codeskulptor >] > list(range(10) >... >... >... >... ) >[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] list(range(10) >... >KeyboardInterrupt > > >> >> Thanks everyone for your suggestions. > >1. You are reading too much >2. Trying to hard > >Think of riding a bicycle. >Cant do it by reading many books on cycling -- thats 1. >Nor by holding the handle so hard you tremble -- thats 2. > >Just relax a bit... >And take small steps > >Chill... as Chris joked, no monster in the computer (or on this list!) > > >> Range(10) stores the min max values and loads each number in between >> when needed. > >It loads?? As in 'load-up-a-van'?? > >When you see: > 10 >10 > >1. Does someone (a clerk maybe) in the computer count to 10? >2. Or do you, seeing that interaction, count to 10? > [If you do, replace the 10 by 1000] >3. Or do you, remember what it means to count to 10 without having to do it? > >Now go back to your statement about 'loading' and find a better verb If I could explain to you why something doesn't work then I could fix it myself. I don't understand why it doesn't work. The best I can do is repost the code. When I use list(range(10)) I get: Traceback (most recent call last): File "C:/Functions/name to number digit.py", line 37, in print (nametonumber(a))#1800 438 2427 837 File "C:/Functions/name to number digit.py", line 10, in nametonumber if y in lst(range(1,10)): TypeError: 'list' object is not callable All the lines I have commented out work. Trying to use list(range(10)) doesn't. (Python 3) http://i.imgur.com/LtiCyZS.jpg It doesn't work. It's broke. :) I don't know what else to say. import string def nametonumber(name): lst=[] nx=[] d
Re: I am out of trial and error again Lists
- On Fri, Oct 24, 2014 5:56 PM CEST Rustom Mody wrote: >On Friday, October 24, 2014 8:11:12 PM UTC+5:30, Seymore4Head wrote: >> On Thu, 23 Oct 2014 21:56:31 -0700 (PDT), Rustom Mody wrote: >> >> >On Thursday, October 23, 2014 10:33:57 PM UTC+5:30, Seymore4Head wrote: >> > On Thu, 23 Oct 2014 15:55:35 + (UTC), Denis McMahon wrote: >> > >> > >On Thu, 23 Oct 2014 10:04:56 -0400, Seymore4Head wrote: >> > > >> > > On Thu, 23 Oct 2014 09:15:16 + (UTC), Denis McMahon wrote: >> > > >> > >>Try the following 3 commands at the console: >> > > >> > >You obviously didn't, so I'll try again. Try each of the following three >> > >commands in the python console at the ">>" prompt. >> > > >> > >1) 10 >> > 10 >> > >> > >2) range(10) >> > range(0, 10) >> > >> > >3) str(range(10)) >> > 'range(0, 10)' >> > [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >> > > >> > >Show *and* describe the output in each case. Describing the output that >> > >you see is actually the key here, as it will allow us to assess whether >> > >you understand what you are actually seeing or not, and if you don't >> > >understand the output you see in the console, then we need to fix that >> > >very fundamental and basic issue before moving on to more complex stuff! >> > > >> > > Ok Thanks >> > > >> > >You were expected to answer the question in the original. I have now set >> > >it as a clearer and more specific task. >> > > >> > >If you're not going to do these things that are intended to help you >> > >learn some of the basic features of the language, then I and everyone >> > >else here that has so far been attempting to help you are wasting our >> > >time. >> > >> > I did try them. I may have missed replying your to your specific >> > comment, but I tried them. >> > >> > BTW str(range (10)) does work with Python 2 which is where I may have >> > got the idea. I happened to be using Python 3 at the time I tried to >> > implement it. It is a little confusing jumping back and forth, but >> > for the moment, I am going to tough it out. u0_a100@condor_umts:/ $ python Python 3.2.2 (default, Jun 23 2014, 00:13:13) [GCC 4.8] on linux-armv7l Type "help", "copyright", "credits" or "license" for more information. >>> list(range(10)) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> >> > I do appreciate all the help too. >> > >> >Hi Seymore! >> > >> >Happy to see that you are moving on from >> >"reading much; understanding nothing; thrashing" >> > >> >to >> > >> >"reading a bit; understanding a bit" >> >[And thanks to Denis to getting you out of your confusion-hole] >> > >> >So heres a small additional question set that I promise will more than repay >> >you your time. >> > >> >Better done in python 2. But if you use python3, below replace >> >range(10) >> >with >> >list(range(10)) > > > > >1. You are reading too much >2. Trying to hard > >Think of riding a bicycle. >Cant do it by reading many books on cycling -- thats 1. >Nor by holding the handle so hard you tremble -- thats 2. > >Just relax a bit... >And take small steps > >Chill... as Chris joked, no monster in the computer (or on this list!) +1 for that remark. Talking about chill: grab a couple of beers (suggest: sixpack) and enjoy an evening of Python! > -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, Oct 25, 2014 at 3:37 AM, Seymore4Head wrote: > When I use list(range(10)) I get: > Traceback (most recent call last): > File "C:/Functions/name to number digit.py", line 37, in > print (nametonumber(a))#1800 438 2427 837 > File "C:/Functions/name to number digit.py", line 10, in > nametonumber > if y in lst(range(1,10)): > TypeError: 'list' object is not callable Now, finally, you're showing us an actual line of code and an actual traceback. And from here, we can see that you misspelled "list". That's why it isn't working. Several people have told you to use the interactive interpreter. Please do so. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
Totally befuddled myself! Are you deliberately misspelling list to lst and hoping the error will go away. And Puh LEESE dont post screen shots of good ol ASCII text -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 10:18:12 PM UTC+5:30, Chris Angelico wrote: > On Sat, Oct 25, 2014 at 3:37 AM, Seymore4Head wrote: > > When I use list(range(10)) I get: > > Traceback (most recent call last): > > File "C:/Functions/name to number digit.py", line 37, in > > print (nametonumber(a))#1800 438 2427 837 > > File "C:/Functions/name to number digit.py", line 10, in > > nametonumber > > if y in lst(range(1,10)): > > TypeError: 'list' object is not callable > > Now, finally, you're showing us an actual line of code and an actual > traceback. And from here, we can see that you misspelled "list". > That's why it isn't working. > > Several people have told you to use the interactive interpreter. Please do so. > > ChrisA Right. Good. Sorry for being impatient Seymore You are now making progress -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, Oct 24, 2014 at 10:37 AM, Seymore4Head wrote: > If I could explain to you why something doesn't work then I could fix > it myself. I don't understand why it doesn't work. The best I can do > is repost the code. You don't need to be able to explain why it doesn't work. You just need to be able to explain what you expected it to do and what it actually did. Posting the code and the traceback that you get is a fine start. > if y in lst(range(1,10)): The name of the builtin is "list". It's a function* that takes an argument and uses it to construct a list, which it returns. "lst" is the name of some specific list that you're using in your code. It's not a function, which is why the error is complaining that it isn't callable. *Actually it's a type object, and calling it causes an instance of the type to be constructed, but for all intents and purposes here it works exactly like a function. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, 25 Oct 2014 03:47:51 +1100, Chris Angelico wrote: >On Sat, Oct 25, 2014 at 3:37 AM, Seymore4Head > wrote: >> When I use list(range(10)) I get: >> Traceback (most recent call last): >> File "C:/Functions/name to number digit.py", line 37, in >> print (nametonumber(a))#1800 438 2427 837 >> File "C:/Functions/name to number digit.py", line 10, in >> nametonumber >> if y in lst(range(1,10)): >> TypeError: 'list' object is not callable > >Now, finally, you're showing us an actual line of code and an actual >traceback. And from here, we can see that you misspelled "list". >That's why it isn't working. > >Several people have told you to use the interactive interpreter. Please do so. > >ChrisA Actually I was a little frustrated when I added that line back in as the other lines all work. Using list(range(10)) Doesn't throw an error but it doesn't work. http://i.imgur.com/DTc5zoL.jpg The interpreter. I don't know how to use that either. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 09:54:23 -0700 (PDT), Rustom Mody wrote: >Totally befuddled myself! > >Are you deliberately misspelling list to lst >and hoping the error will go away. > >And Puh LEESE >dont post screen shots of good ol ASCII text I didn't do that on purpose. I make a lot of typing mistakes. Sorry -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 10:06:47 PM UTC+5:30, Ian wrote: > On Fri, Oct 24, 2014 at 9:56 AM, Rustom Mody wrote: > >> Range(10) stores the min max values and loads each number in between > >> when needed. > > > > It loads?? As in 'load-up-a-van'?? > > As in loads into memory. > > > When you see: > > > 10 > > 10 > > > > 1. Does someone (a clerk maybe) in the computer count to 10? > > 2. Or do you, seeing that interaction, count to 10? > >[If you do, replace the 10 by 1000] > > 3. Or do you, remember what it means to count to 10 without having to do it? > > I don't understand why you think any of these are implied by the word "load". > > > Now go back to your statement about 'loading' and find a better verb > > I presume he used "load" because that was the word I used in my > explanatory post about the difference between range in Python 2 and > Python 3 yesterday. I would be very surprised (Ian) if we had any essential disagreement on this subject. [JFTR I see nothing wrong with your explanation] I would also be (pleasantly) surprised if Seymore were to benefit by these discussions at this stage. So is it ok if we drop it here (or start a new thread)? -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, Oct 25, 2014 at 4:05 AM, Ian Kelly wrote: > The name of the builtin is "list". It's a function* that takes an > argument and uses it to construct a list, which it returns. > > *Actually it's a type object, and calling it causes an instance of the > type to be constructed, but for all intents and purposes here it works > exactly like a function. It's callable, that's all that matters. callable(object) -> bool Return whether the object is callable (i.e., some kind of function). :) ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 19:03:47 +0200, Seymore4Head wrote: http://i.imgur.com/DTc5zoL.jpg The interpreter. I don't know how to use that either. It's what's on the left hand side of your screenshot. You can simply type Python statements following the >>> prompt and hit enter to examine the result, instead of pushing F5 to run your code -- Vriendelijke groeten / Kind regards, Albert Visser Using Opera's mail client: http://www.opera.com/mail/ -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 10:37:45 PM UTC+5:30, Seymore4Head wrote: > On Fri, 24 Oct 2014 09:54:23 -0700 (PDT), Rustom Mody wrote: > > >Totally befuddled myself! > > > >Are you deliberately misspelling list to lst > >and hoping the error will go away. > > > >And Puh LEESE > >dont post screen shots of good ol ASCII text > > I didn't do that on purpose. I make a lot of typing mistakes. > Sorry Right No sweat! I was genuinely asking: - Did you mis-spell list as lst? - Or did you go thrashing (Steven gave a picturesque description) just changing things until the error went? [Believe you me, I do the same when I am in a strange place and I am searching for something in my (suit|brief)case ] -- https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
On Fri, Oct 24, 2014 at 1:38 AM, Steven D'Aprano wrote: > I don't get why that's considered hard to read. > So why is it hard to read when the index is a flag? > > value = [f, g][cond]() It's clear to you, it's clear to me, but is it clear to everyone? I very much doubt it. Also, you've gone to the trouble of def'ing two functions here - you may as well do a function for the if/else. -- https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
On 10/22/2014 01:29 AM, ast wrote: Hello Is there in Python something like: j = (j >= 10) ? 3 : j+1; as in C language ? thx Out of all of the replies, I don't think anyone actually offered the answer: a if condition else b -- https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
On Sat, Oct 25, 2014 at 4:23 AM, Tobiah wrote: > Out of all of the replies, I don't think anyone > actually offered the answer: > > > a if condition else b Jean-Michel did, the very first response. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 19:18:12 +0200, "Albert Visser" wrote: >On Fri, 24 Oct 2014 19:03:47 +0200, Seymore4Head > wrote: > >> >> http://i.imgur.com/DTc5zoL.jpg >> >> The interpreter. I don't know how to use that either. >> > >It's what's on the left hand side of your screenshot. You can simply type >Python statements following the >>> prompt and hit enter to examine the >result, instead of pushing F5 to run your code I guess I am confusing the Interpreter with the debugger. Someone suggested I use the Interpreter to step through line by line. I don't know how to do that. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 10:55:44 PM UTC+5:30, Seymore4Head wrote:
> On Fri, 24 Oct 2014 19:18:12 +0200, "Albert Visser" wrote:
>
> >On Fri, 24 Oct 2014 19:03:47 +0200, Seymore4Head wrote:
> >
> >>
> >> http://i.imgur.com/DTc5zoL.jpg
> >>
> >> The interpreter. I don't know how to use that either.
> >>
> >
> >It's what's on the left hand side of your screenshot. You can simply type
> >Python statements following the >>> prompt and hit enter to examine the
> >result, instead of pushing F5 to run your code
>
> I guess I am confusing the Interpreter with the debugger. Someone
> suggested I use the Interpreter to step through line by line.
> I don't know how to do that.
Dont bother with the debugger just yet.
For most python programmers, sticking a few print statements
(expressions in python 3) in adroitly is good enough.*
For now best if you concentrate on
1. What are the features of python -- the language
2. What are the standard data types and functions -- the libraries
3. How to use and jump between the two windows of your screenshot most
effectively. What you should and should not type in each etc
* One neat trick of using the print to debug.
Say you have a line like
nx.append("2")
and nx is not getting to be what you expect.
Change it to
nx.append("2"); print(nx)
Cleaning up the print after debugging is easier than if you use a
separate line like so
nx.append("2")
print(nx)
[I think I learnt this trick from Mark Lawrence]
--
https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head wrote: > Actually I was a little frustrated when I added that line back in as > the other lines all work. > Using list(range(10)) Doesn't throw an error but it doesn't work. > > http://i.imgur.com/DTc5zoL.jpg > > The interpreter. I don't know how to use that either. Try both of these in the interpreter, and observe the difference: 7 in range(10) "7" in range(10) Do you understand what the difference between 7 and "7" is? -- https://mail.python.org/mailman/listinfo/python-list
Re: (-1)**1000
Terry Reedy Wrote in message: > On 10/22/2014 4:27 AM, ast wrote: >> Hello >> >> If i am writing (-1)**1000 on a python program, will the >> interpreter do (-1)*(-1)*...*(-1) or something clever ? > > The answer depends on the implementation. > >> In fact i have (-1)**N with N an integer potentially big. >> >> I do some tests that suggest that Python is clever > > You probably mean "CPython is clever". Other implementations may or may > not have the same optimizations. > I can see several potential optimizations for x**n. Some the CPython implementation does, others I don't know. First, if the two component numbers are known at function compile time, evaluate at compile time. If x is known at compile time to be -1, and n is a non negative integer, just mask the bottom bit of n, and choose -1 or 1 based on that bit. There are other special values, such as 0, -1. If x is a power of 2, and n is an int, then count the trailing zeroes of x, multiply that by n, and construct a (binary) value with that many trailing zeroes. If x isn't any of the above, but n is a postive int, use the square and multiply technique, which is of order log(n). In particular for n of a billion (10**9), it can be done in about 60 multiplies. If neither value is known at compile time, it may still be worth checking for some of these, such as the last. And if x is a float, the last optimization has the advantage of improving accuracy as well as speed. -- DaveA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 10:42:08 -0700 (PDT), Rustom Mody
wrote:
>On Friday, October 24, 2014 10:55:44 PM UTC+5:30, Seymore4Head wrote:
>> On Fri, 24 Oct 2014 19:18:12 +0200, "Albert Visser" wrote:
>>
>> >On Fri, 24 Oct 2014 19:03:47 +0200, Seymore4Head wrote:
>> >
>> >>
>> >> http://i.imgur.com/DTc5zoL.jpg
>> >>
>> >> The interpreter. I don't know how to use that either.
>> >>
>> >
>> >It's what's on the left hand side of your screenshot. You can simply type
>> >Python statements following the >>> prompt and hit enter to examine the
>> >result, instead of pushing F5 to run your code
>>
>> I guess I am confusing the Interpreter with the debugger. Someone
>> suggested I use the Interpreter to step through line by line.
>> I don't know how to do that.
>
>Dont bother with the debugger just yet.
>For most python programmers, sticking a few print statements
>(expressions in python 3) in adroitly is good enough.*
>
>For now best if you concentrate on
>1. What are the features of python -- the language
>2. What are the standard data types and functions -- the libraries
>3. How to use and jump between the two windows of your screenshot most
> effectively. What you should and should not type in each etc
>
>* One neat trick of using the print to debug.
>Say you have a line like
>
>nx.append("2")
>
>and nx is not getting to be what you expect.
>Change it to
>
>nx.append("2"); print(nx)
>
>Cleaning up the print after debugging is easier than if you use a
>separate line like so
>
>nx.append("2")
>print(nx)
>
>[I think I learnt this trick from Mark Lawrence]
Useful tips
Thanks
--
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly
wrote:
>On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head
> wrote:
>> Actually I was a little frustrated when I added that line back in as
>> the other lines all work.
>> Using list(range(10)) Doesn't throw an error but it doesn't work.
>>
>> http://i.imgur.com/DTc5zoL.jpg
>>
>> The interpreter. I don't know how to use that either.
>
>Try both of these in the interpreter, and observe the difference:
>
>7 in range(10)
>
>"7" in range(10)
>
>Do you understand what the difference between 7 and "7" is?
I do understand that. 7 is a number and "7" is a string.
What my question was...and still is...is why
Python 3 fails when I try using
y=1 800 get charter
y in range str(range(10))
should work because y is a string and str(range(10)) should be
"y" in str(1) fails.
It doesn't give an error it's just not True when y is a number.
These hints are just not working. I am too thick for hints. :)
If you could use it in the code, I might understand.
The other work arounds that were posted work.
I have used them. str(range(10)) doesn't work.
import string
def nametonumber(name):
lst=[]
nx=[]
digit=[]
digit="".join(str(i) for i in range(10))
for x in name:
lst.append(x)
for y in (lst):
if y in list(range(1,10)):
#if y in "1234567890":
#if y.isdigit():
#if y in digit:
#if y in string.digits:
nx.append(y)
if y in " -()":
nx.append(y)
if y in "abc":
nx.append("2")
if y in "def":
nx.append("3")
if y in "ghi":
nx.append("4")
if y in "jkl":
nx.append("5")
if y in "mno":
nx.append("6")
if y in "pqrs":
nx.append("7")
if y in "tuv":
nx.append("8")
if y in "wxyz":
nx.append("9")
number="".join(e for e in nx)
return number
a="1-800-getcharter"
print (nametonumber(a))#1800 438 2427 837
a="1-800-leo laporte"
print (nametonumber(a))
a="1 800 dialaho"
print (nametonumber(a))
Please
--
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Re: (test) ? a:b
On Fri, Oct 24, 2014 at 7:07 AM, Steven D'Aprano >> if j < 10: >> j += 1 >> else: >> j = 3 >> >> or: >> >> j = j + 1 if j < 10 else 3 >> >> or: >> >> j = (lambda: 3, lambda: j + 1)[j < 10]() > > Certainly not the third one. That's needlessly obfuscated for the sake of > premature optimization. This version is much better, and probably not only > simpler and easier to read but probably more efficient too: > > j = (3, j + 1)[j < 10] Yes, the lambda approach falls victim to function calls being slow. $ python3 -m timeit -s "j = 5" "if j < 10: j+=1 > else: j=3" 1000 loops, best of 3: 0.0513 usec per loop $ python3 -m timeit -s "j = 5" "j = j + 1 if j < 10 else 3" 1000 loops, best of 3: 0.0519 usec per loop $ python3 -m timeit -s "j = 5" "j = (3, j+1)[j < 10]" 1000 loops, best of 3: 0.0883 usec per loop $ python3 -m timeit -s "j = 5" "j = (lambda: 3, lambda: j+1)[j < 10]()" 100 loops, best of 3: 0.312 usec per loop -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
I meant to type:
if y in range(1,10) doesn't work.
Sigh
Sorry
On Fri, 24 Oct 2014 14:15:13 -0400, Seymore4Head
wrote:
>On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly
>wrote:
>
>>On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head
>> wrote:
>>> Actually I was a little frustrated when I added that line back in as
>>> the other lines all work.
>>> Using list(range(10)) Doesn't throw an error but it doesn't work.
>>>
>>> http://i.imgur.com/DTc5zoL.jpg
>>>
>>> The interpreter. I don't know how to use that either.
>>
>>Try both of these in the interpreter, and observe the difference:
>>
>>7 in range(10)
>>
>>"7" in range(10)
>>
>>Do you understand what the difference between 7 and "7" is?
>
>I do understand that. 7 is a number and "7" is a string.
>What my question was...and still is...is why
>Python 3 fails when I try using
>y=1 800 get charter
>
>y in range str(range(10))
>should work because y is a string and str(range(10)) should be
>"y" in str(1) fails.
>It doesn't give an error it's just not True when y is a number.
>
>These hints are just not working. I am too thick for hints. :)
>If you could use it in the code, I might understand.
>The other work arounds that were posted work.
>I have used them. str(range(10)) doesn't work.
>
>import string
>def nametonumber(name):
>lst=[]
>nx=[]
>digit=[]
>digit="".join(str(i) for i in range(10))
>for x in name:
>lst.append(x)
>for y in (lst):
>if y in list(range(1,10)):
>#if y in "1234567890":
>#if y.isdigit():
>#if y in digit:
>#if y in string.digits:
>nx.append(y)
>if y in " -()":
>nx.append(y)
>if y in "abc":
>nx.append("2")
>if y in "def":
>nx.append("3")
>if y in "ghi":
>nx.append("4")
>if y in "jkl":
>nx.append("5")
>if y in "mno":
>nx.append("6")
>if y in "pqrs":
>nx.append("7")
>if y in "tuv":
>nx.append("8")
>if y in "wxyz":
>nx.append("9")
>number="".join(e for e in nx)
>return number
>a="1-800-getcharter"
>print (nametonumber(a))#1800 438 2427 837
>a="1-800-leo laporte"
>print (nametonumber(a))
>a="1 800 dialaho"
>print (nametonumber(a))
>
>Please
>
--
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Re: I am out of trial and error again Lists
On 24/10/2014 18:03, Seymore4Head wrote: Actually I was a little frustrated when I added that line back in as the other lines all work. Using list(range(10)) Doesn't throw an error but it doesn't work. http://i.imgur.com/DTc5zoL.jpg The interpreter. I don't know how to use that either. You've stated that you can use google so why not try it to find out about the interpreter? Or simply navigate to docs.python.org and see what the contents or index tell you? Failing that carry on charging around like a headless chicken and hope that the extremely patient folk here keep helping you out. -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
On 10/24/2014 10:27 AM, Chris Angelico wrote: On Sat, Oct 25, 2014 at 4:23 AM, Tobiah wrote: Out of all of the replies, I don't think anyone actually offered the answer: a if condition else b Jean-Michel did, the very first response. ChrisA I had to search for it. For some reason Thunderbird didn't thread that message with all the others. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On 24/10/2014 19:20, Seymore4Head wrote: I meant to type: if y in range(1,10) doesn't work. Sigh Sorry How many more times, state what you expect to happen and what actually happens. "doesn't work" is useless. Please read this http://sscce.org/ -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence -- https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
Ian Kelly : >> j = (lambda: 3, lambda: j + 1)[j < 10]() > Yes, the lambda approach falls victim to function calls being slow. That's just a deficiency in the compiler. There's nothing there that prevents the optimizer from translating the expression into the equivalent if statement. At any rate, the only issue at hand is the obviousness of the idiom. You should generally choose the syntax that best expresses the logic of the program. Marko -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 11:17:53 AM UTC-7, Seymore4Head wrote:
> On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly
> wrote:
>
> >On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head
> > wrote:
> >> Actually I was a little frustrated when I added that line back in as
> >> the other lines all work.
> >> Using list(range(10)) Doesn't throw an error but it doesn't work.
> >>
> >> http://i.imgur.com/DTc5zoL.jpg
> >>
> >> The interpreter. I don't know how to use that either.
> >
> >Try both of these in the interpreter, and observe the difference:
> >
> >7 in range(10)
> >
> >"7" in range(10)
> >
> >Do you understand what the difference between 7 and "7" is?
>
> I do understand that. 7 is a number and "7" is a string.
> What my question was...and still is...is why
> Python 3 fails when I try using
> y=1 800 get charter
>
> y in range str(range(10))
> should work because y is a string and str(range(10)) should be
> "y" in str(1) fails.
> It doesn't give an error it's just not True when y is a number.
>
> These hints are just not working. I am too thick for hints. :)
> If you could use it in the code, I might understand.
> The other work arounds that were posted work.
> I have used them. str(range(10)) doesn't work.
>
> import string
> def nametonumber(name):
> lst=[]
> nx=[]
> digit=[]
> digit="".join(str(i) for i in range(10))
> for x in name:
> lst.append(x)
> for y in (lst):
> if y in list(range(1,10)):
> #if y in "1234567890":
> #if y.isdigit():
> #if y in digit:
> #if y in string.digits:
> nx.append(y)
> if y in " -()":
> nx.append(y)
> if y in "abc":
> nx.append("2")
> if y in "def":
> nx.append("3")
> if y in "ghi":
> nx.append("4")
> if y in "jkl":
> nx.append("5")
> if y in "mno":
> nx.append("6")
> if y in "pqrs":
> nx.append("7")
> if y in "tuv":
> nx.append("8")
> if y in "wxyz":
> nx.append("9")
> number="".join(e for e in nx)
> return number
> a="1-800-getcharter"
> print (nametonumber(a))#1800 438 2427 837
> a="1-800-leo laporte"
> print (nametonumber(a))
> a="1 800 dialaho"
> print (nametonumber(a))
>
> Please
Your code here is actually pretty close to a correct answer. Just a few things
to consider...
- Why are you converting your name string to a list? It is unnecessary. When
you do "for y in ", then y will still be single characters on each
iteration of the loop.
- "if y in string.digits" should work fine.
- "if y in list(range(1,10)" won't work for two reasons: First, it creates a
list of numbers, not strings. Second, even if it did, it would be missing the
"0" digit.
- At the end, when you convert your list to a string, you don't need to use
list comprehension, since nx is already a list. number = "".join(nx) should
work fine.
Also, in general, you need to stop and slow down and think like a programmer.
If you get an error, your instinct shouldn't be to just hack at it to make the
error go away. Look at the error and try to make sense of it. Learn what the
error means and try to fix the core problem.
And for @#$%'s sake...stop saying "It isn't working" and not elaborating.
You've been told by every other post in this thread to show us what you did and
what the error was. You've also been told to *NOT* retype what you see and to
copy/paste your code and the error because when you make a typo when copying,
we might see a problem that doesn't exist and then you just get more confused.
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 19:40:39 +0100, Mark Lawrence
wrote:
>On 24/10/2014 19:20, Seymore4Head wrote:
>> I meant to type:
>> if y in range(1,10) doesn't work.
>> Sigh
>> Sorry
>>
>
>How many more times, state what you expect to happen and what actually
>happens. "doesn't work" is useless. Please read this http://sscce.org/
Good suggestion.
OK how is this?
It doesn't print what I expect.
Does it print what you expect?
name="123-xyz-abc"
for x in name:
if x in range(10):
print ("Range",(x))
if x in str(range(10)):
print ("String range",(x))
http://i.imgur.com/EGKUpAb.jpg
--
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 11:57:12 -0700 (PDT), [email protected] wrote: >On Friday, October 24, 2014 11:17:53 AM UTC-7, Seymore4Head wrote: >> On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly >> wrote: >> >> >On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head >> > wrote: >> >> Actually I was a little frustrated when I added that line back in as >> >> the other lines all work. >> >> Using list(range(10)) Doesn't throw an error but it doesn't work. >> >> >> >> http://i.imgur.com/DTc5zoL.jpg >> >> >> >> The interpreter. I don't know how to use that either. >> > >> >Try both of these in the interpreter, and observe the difference: >> > >> >7 in range(10) >> > >> >"7" in range(10) >> > >> >Do you understand what the difference between 7 and "7" is? >> >> I do understand that. 7 is a number and "7" is a string. >> What my question was...and still is...is why >> Python 3 fails when I try using >> y=1 800 get charter >> >> y in range str(range(10)) >> should work because y is a string and str(range(10)) should be >> "y" in str(1) fails. >> It doesn't give an error it's just not True when y is a number. >> >> These hints are just not working. I am too thick for hints. :) >> If you could use it in the code, I might understand. >> The other work arounds that were posted work. >> I have used them. str(range(10)) doesn't work. >> >> import string >> def nametonumber(name): >> lst=[] >> nx=[] >> digit=[] >> digit="".join(str(i) for i in range(10)) >> for x in name: >> lst.append(x) >> for y in (lst): >> if y in list(range(1,10)): >> #if y in "1234567890": >> #if y.isdigit(): >> #if y in digit: >> #if y in string.digits: >> nx.append(y) >> if y in " -()": >> nx.append(y) >> if y in "abc": >> nx.append("2") >> if y in "def": >> nx.append("3") >> if y in "ghi": >> nx.append("4") >> if y in "jkl": >> nx.append("5") >> if y in "mno": >> nx.append("6") >> if y in "pqrs": >> nx.append("7") >> if y in "tuv": >> nx.append("8") >> if y in "wxyz": >> nx.append("9") >> number="".join(e for e in nx) >> return number >> a="1-800-getcharter" >> print (nametonumber(a))#1800 438 2427 837 >> a="1-800-leo laporte" >> print (nametonumber(a)) >> a="1 800 dialaho" >> print (nametonumber(a)) >> >> Please > >Your code here is actually pretty close to a correct answer. Just a few >things to consider... > >- Why are you converting your name string to a list? It is unnecessary. When >you do "for y in ", then y will still be single characters on >each iteration of the loop. > >- "if y in string.digits" should work fine. > >- "if y in list(range(1,10)" won't work for two reasons: First, it creates a >list of numbers, not strings. Second, even if it did, it would be missing the >"0" digit. > >- At the end, when you convert your list to a string, you don't need to use >list comprehension, since nx is already a list. number = "".join(nx) should >work fine. > >Also, in general, you need to stop and slow down and think like a programmer. >If you get an error, your instinct shouldn't be to just hack at it to make the >error go away. Look at the error and try to make sense of it. Learn what the >error means and try to fix the core problem. > >And for @#$%'s sake...stop saying "It isn't working" and not elaborating. >You've been told by every other post in this thread to show us what you did >and what the error was. You've also been told to *NOT* retype what you see >and to copy/paste your code and the error because when you make a typo when >copying, we might see a problem that doesn't exist and then you just get more >confused. Ok I think I may have the question you guys are looking for. I just posted it. See above. But it's still broke. :( -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 12:12:10 PM UTC-7, Seymore4Head wrote: > On Fri, 24 Oct 2014 11:57:12 -0700 (PDT), [email protected] wrote: > > >On Friday, October 24, 2014 11:17:53 AM UTC-7, Seymore4Head wrote: > >> On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly > >> wrote: > >> > >> >On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head > >> > wrote: > >> >> Actually I was a little frustrated when I added that line back in as > >> >> the other lines all work. > >> >> Using list(range(10)) Doesn't throw an error but it doesn't work. > >> >> > >> >> http://i.imgur.com/DTc5zoL.jpg > >> >> > >> >> The interpreter. I don't know how to use that either. > >> > > >> >Try both of these in the interpreter, and observe the difference: > >> > > >> >7 in range(10) > >> > > >> >"7" in range(10) > >> > > >> >Do you understand what the difference between 7 and "7" is? > >> > >> I do understand that. 7 is a number and "7" is a string. > >> What my question was...and still is...is why > >> Python 3 fails when I try using > >> y=1 800 get charter > >> > >> y in range str(range(10)) > >> should work because y is a string and str(range(10)) should be > >> "y" in str(1) fails. > >> It doesn't give an error it's just not True when y is a number. > >> > >> These hints are just not working. I am too thick for hints. :) > >> If you could use it in the code, I might understand. > >> The other work arounds that were posted work. > >> I have used them. str(range(10)) doesn't work. > >> > >> import string > >> def nametonumber(name): > >> lst=[] > >> nx=[] > >> digit=[] > >> digit="".join(str(i) for i in range(10)) > >> for x in name: > >> lst.append(x) > >> for y in (lst): > >> if y in list(range(1,10)): > >> #if y in "1234567890": > >> #if y.isdigit(): > >> #if y in digit: > >> #if y in string.digits: > >> nx.append(y) > >> if y in " -()": > >> nx.append(y) > >> if y in "abc": > >> nx.append("2") > >> if y in "def": > >> nx.append("3") > >> if y in "ghi": > >> nx.append("4") > >> if y in "jkl": > >> nx.append("5") > >> if y in "mno": > >> nx.append("6") > >> if y in "pqrs": > >> nx.append("7") > >> if y in "tuv": > >> nx.append("8") > >> if y in "wxyz": > >> nx.append("9") > >> number="".join(e for e in nx) > >> return number > >> a="1-800-getcharter" > >> print (nametonumber(a))#1800 438 2427 837 > >> a="1-800-leo laporte" > >> print (nametonumber(a)) > >> a="1 800 dialaho" > >> print (nametonumber(a)) > >> > >> Please > > > >Your code here is actually pretty close to a correct answer. Just a few > >things to consider... > > > >- Why are you converting your name string to a list? It is unnecessary. > >When you do "for y in ", then y will still be single characters > >on each iteration of the loop. > > > >- "if y in string.digits" should work fine. > > > >- "if y in list(range(1,10)" won't work for two reasons: First, it creates a > >list of numbers, not strings. Second, even if it did, it would be missing > >the "0" digit. > > > >- At the end, when you convert your list to a string, you don't need to use > >list comprehension, since nx is already a list. number = "".join(nx) should > >work fine. > > > >Also, in general, you need to stop and slow down and think like a > >programmer. If you get an error, your instinct shouldn't be to just hack at > >it to make the error go away. Look at the error and try to make sense of > >it. Learn what the error means and try to fix the core problem. > > > >And for @#$%'s sake...stop saying "It isn't working" and not elaborating. > >You've been told by every other post in this thread to show us what you did > >and what the error was. You've also been told to *NOT* retype what you see > >and to copy/paste your code and the error because when you make a typo when > >copying, we might see a problem that doesn't exist and then you just get > >more confused. > > Ok I think I may have the question you guys are looking for. > I just posted it. > See above. > > But it's still broke. :( str(range(10)) doesn't do what you think it does. Run 'print(str(range(10)))' and look at what you get. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 12:25:33 -0700 (PDT), [email protected] wrote: >On Friday, October 24, 2014 12:12:10 PM UTC-7, Seymore4Head wrote: >> On Fri, 24 Oct 2014 11:57:12 -0700 (PDT), [email protected] wrote: >> >> >On Friday, October 24, 2014 11:17:53 AM UTC-7, Seymore4Head wrote: >> >> On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly >> >> wrote: >> >> >> >> >On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head >> >> > wrote: >> >> >> Actually I was a little frustrated when I added that line back in as >> >> >> the other lines all work. >> >> >> Using list(range(10)) Doesn't throw an error but it doesn't work. >> >> >> >> >> >> http://i.imgur.com/DTc5zoL.jpg >> >> >> >> >> >> The interpreter. I don't know how to use that either. >> >> > >> >> >Try both of these in the interpreter, and observe the difference: >> >> > >> >> >7 in range(10) >> >> > >> >> >"7" in range(10) >> >> > >> >> >Do you understand what the difference between 7 and "7" is? >> >> >> >> I do understand that. 7 is a number and "7" is a string. >> >> What my question was...and still is...is why >> >> Python 3 fails when I try using >> >> y=1 800 get charter >> >> >> >> y in range str(range(10)) >> >> should work because y is a string and str(range(10)) should be >> >> "y" in str(1) fails. >> >> It doesn't give an error it's just not True when y is a number. >> >> >> >> These hints are just not working. I am too thick for hints. :) >> >> If you could use it in the code, I might understand. >> >> The other work arounds that were posted work. >> >> I have used them. str(range(10)) doesn't work. >> >> >> >> import string >> >> def nametonumber(name): >> >> lst=[] >> >> nx=[] >> >> digit=[] >> >> digit="".join(str(i) for i in range(10)) >> >> for x in name: >> >> lst.append(x) >> >> for y in (lst): >> >> if y in list(range(1,10)): >> >> #if y in "1234567890": >> >> #if y.isdigit(): >> >> #if y in digit: >> >> #if y in string.digits: >> >> nx.append(y) >> >> if y in " -()": >> >> nx.append(y) >> >> if y in "abc": >> >> nx.append("2") >> >> if y in "def": >> >> nx.append("3") >> >> if y in "ghi": >> >> nx.append("4") >> >> if y in "jkl": >> >> nx.append("5") >> >> if y in "mno": >> >> nx.append("6") >> >> if y in "pqrs": >> >> nx.append("7") >> >> if y in "tuv": >> >> nx.append("8") >> >> if y in "wxyz": >> >> nx.append("9") >> >> number="".join(e for e in nx) >> >> return number >> >> a="1-800-getcharter" >> >> print (nametonumber(a))#1800 438 2427 837 >> >> a="1-800-leo laporte" >> >> print (nametonumber(a)) >> >> a="1 800 dialaho" >> >> print (nametonumber(a)) >> >> >> >> Please >> > >> >Your code here is actually pretty close to a correct answer. Just a few >> >things to consider... >> > >> >- Why are you converting your name string to a list? It is unnecessary. >> >When you do "for y in ", then y will still be single >> >characters on each iteration of the loop. >> > >> >- "if y in string.digits" should work fine. >> > >> >- "if y in list(range(1,10)" won't work for two reasons: First, it creates >> >a list of numbers, not strings. Second, even if it did, it would be >> >missing the "0" digit. >> > >> >- At the end, when you convert your list to a string, you don't need to use >> >list comprehension, since nx is already a list. number = "".join(nx) >> >should work fine. >> > >> >Also, in general, you need to stop and slow down and think like a >> >programmer. If you get an error, your instinct shouldn't be to just hack >> >at it to make the error go away. Look at the error and try to make sense >> >of it. Learn what the error means and try to fix the core problem. >> > >> >And for @#$%'s sake...stop saying "It isn't working" and not elaborating. >> >You've been told by every other post in this thread to show us what you did >> >and what the error was. You've also been told to *NOT* retype what you see >> >and to copy/paste your code and the error because when you make a typo when >> >copying, we might see a problem that doesn't exist and then you just get >> >more confused. >> >> Ok I think I may have the question you guys are looking for. >> I just posted it. >> See above. >> >> But it's still broke. :( > >str(range(10)) doesn't do what you think it does. > >Run 'print(str(range(10)))' and look at what you get. Yeah, I know that. My question is why? The answer was that Python 3 only stores the min and max values but you can still iterate over them. I don't think that means what I think it means. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Friday, October 24, 2014 12:36:23 PM UTC-7, Seymore4Head wrote: > On Fri, 24 Oct 2014 12:25:33 -0700 (PDT), [email protected] wrote: > > >On Friday, October 24, 2014 12:12:10 PM UTC-7, Seymore4Head wrote: > >> On Fri, 24 Oct 2014 11:57:12 -0700 (PDT), [email protected] wrote: > >> > >> >On Friday, October 24, 2014 11:17:53 AM UTC-7, Seymore4Head wrote: > >> >> On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly > >> >> wrote: > >> >> > >> >> >On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head > >> >> > wrote: > >> >> >> Actually I was a little frustrated when I added that line back in as > >> >> >> the other lines all work. > >> >> >> Using list(range(10)) Doesn't throw an error but it doesn't work. > >> >> >> > >> >> >> http://i.imgur.com/DTc5zoL.jpg > >> >> >> > >> >> >> The interpreter. I don't know how to use that either. > >> >> > > >> >> >Try both of these in the interpreter, and observe the difference: > >> >> > > >> >> >7 in range(10) > >> >> > > >> >> >"7" in range(10) > >> >> > > >> >> >Do you understand what the difference between 7 and "7" is? > >> >> > >> >> I do understand that. 7 is a number and "7" is a string. > >> >> What my question was...and still is...is why > >> >> Python 3 fails when I try using > >> >> y=1 800 get charter > >> >> > >> >> y in range str(range(10)) > >> >> should work because y is a string and str(range(10)) should be > >> >> "y" in str(1) fails. > >> >> It doesn't give an error it's just not True when y is a number. > >> >> > >> >> These hints are just not working. I am too thick for hints. :) > >> >> If you could use it in the code, I might understand. > >> >> The other work arounds that were posted work. > >> >> I have used them. str(range(10)) doesn't work. > >> >> > >> >> import string > >> >> def nametonumber(name): > >> >> lst=[] > >> >> nx=[] > >> >> digit=[] > >> >> digit="".join(str(i) for i in range(10)) > >> >> for x in name: > >> >> lst.append(x) > >> >> for y in (lst): > >> >> if y in list(range(1,10)): > >> >> #if y in "1234567890": > >> >> #if y.isdigit(): > >> >> #if y in digit: > >> >> #if y in string.digits: > >> >> nx.append(y) > >> >> if y in " -()": > >> >> nx.append(y) > >> >> if y in "abc": > >> >> nx.append("2") > >> >> if y in "def": > >> >> nx.append("3") > >> >> if y in "ghi": > >> >> nx.append("4") > >> >> if y in "jkl": > >> >> nx.append("5") > >> >> if y in "mno": > >> >> nx.append("6") > >> >> if y in "pqrs": > >> >> nx.append("7") > >> >> if y in "tuv": > >> >> nx.append("8") > >> >> if y in "wxyz": > >> >> nx.append("9") > >> >> number="".join(e for e in nx) > >> >> return number > >> >> a="1-800-getcharter" > >> >> print (nametonumber(a))#1800 438 2427 837 > >> >> a="1-800-leo laporte" > >> >> print (nametonumber(a)) > >> >> a="1 800 dialaho" > >> >> print (nametonumber(a)) > >> >> > >> >> Please > >> > > >> >Your code here is actually pretty close to a correct answer. Just a few > >> >things to consider... > >> > > >> >- Why are you converting your name string to a list? It is unnecessary. > >> >When you do "for y in ", then y will still be single > >> >characters on each iteration of the loop. > >> > > >> >- "if y in string.digits" should work fine. > >> > > >> >- "if y in list(range(1,10)" won't work for two reasons: First, it > >> >creates a list of numbers, not strings. Second, even if it did, it would > >> >be missing the "0" digit. > >> > > >> >- At the end, when you convert your list to a string, you don't need to > >> >use list comprehension, since nx is already a list. number = "".join(nx) > >> >should work fine. > >> > > >> >Also, in general, you need to stop and slow down and think like a > >> >programmer. If you get an error, your instinct shouldn't be to just hack > >> >at it to make the error go away. Look at the error and try to make sense > >> >of it. Learn what the error means and try to fix the core problem. > >> > > >> >And for @#$%'s sake...stop saying "It isn't working" and not elaborating. > >> > You've been told by every other post in this thread to show us what you > >> >did and what the error was. You've also been told to *NOT* retype what > >> >you see and to copy/paste your code and the error because when you make a > >> >typo when copying, we might see a problem that doesn't exist and then you > >> >just get more confused. > >> > >> Ok I think I may have the question you guys are looking for. > >> I just posted it. > >> See above. > >> > >> But it's still broke. :( > > > >str(range(10)) doesn't do what you think it does. > > > >Run 'print(str(range(10)))' and look at what you get. > > Yeah, I know that. My question is why? > The answer was that Python 3 only stores the min and max values
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 12:55:19 -0700 (PDT), [email protected] wrote: >On Friday, October 24, 2014 12:36:23 PM UTC-7, Seymore4Head wrote: >> On Fri, 24 Oct 2014 12:25:33 -0700 (PDT), [email protected] wrote: >> >> >On Friday, October 24, 2014 12:12:10 PM UTC-7, Seymore4Head wrote: >> >> On Fri, 24 Oct 2014 11:57:12 -0700 (PDT), [email protected] wrote: >> >> >> >> >On Friday, October 24, 2014 11:17:53 AM UTC-7, Seymore4Head wrote: >> >> >> On Fri, 24 Oct 2014 11:52:15 -0600, Ian Kelly >> >> >> wrote: >> >> >> >> >> >> >On Fri, Oct 24, 2014 at 11:03 AM, Seymore4Head >> >> >> > wrote: >> >> >> >> Actually I was a little frustrated when I added that line back in as >> >> >> >> the other lines all work. >> >> >> >> Using list(range(10)) Doesn't throw an error but it doesn't work. >> >> >> >> >> >> >> >> http://i.imgur.com/DTc5zoL.jpg >> >> >> >> >> >> >> >> The interpreter. I don't know how to use that either. >> >> >> > >> >> >> >Try both of these in the interpreter, and observe the difference: >> >> >> > >> >> >> >7 in range(10) >> >> >> > >> >> >> >"7" in range(10) >> >> >> > >> >> >> >Do you understand what the difference between 7 and "7" is? >> >> >> >> >> >> I do understand that. 7 is a number and "7" is a string. >> >> >> What my question was...and still is...is why >> >> >> Python 3 fails when I try using >> >> >> y=1 800 get charter >> >> >> >> >> >> y in range str(range(10)) >> >> >> should work because y is a string and str(range(10)) should be >> >> >> "y" in str(1) fails. >> >> >> It doesn't give an error it's just not True when y is a number. >> >> >> >> >> >> These hints are just not working. I am too thick for hints. :) >> >> >> If you could use it in the code, I might understand. >> >> >> The other work arounds that were posted work. >> >> >> I have used them. str(range(10)) doesn't work. >> >> >> >> >> >> import string >> >> >> def nametonumber(name): >> >> >> lst=[] >> >> >> nx=[] >> >> >> digit=[] >> >> >> digit="".join(str(i) for i in range(10)) >> >> >> for x in name: >> >> >> lst.append(x) >> >> >> for y in (lst): >> >> >> if y in list(range(1,10)): >> >> >> #if y in "1234567890": >> >> >> #if y.isdigit(): >> >> >> #if y in digit: >> >> >> #if y in string.digits: >> >> >> nx.append(y) >> >> >> if y in " -()": >> >> >> nx.append(y) >> >> >> if y in "abc": >> >> >> nx.append("2") >> >> >> if y in "def": >> >> >> nx.append("3") >> >> >> if y in "ghi": >> >> >> nx.append("4") >> >> >> if y in "jkl": >> >> >> nx.append("5") >> >> >> if y in "mno": >> >> >> nx.append("6") >> >> >> if y in "pqrs": >> >> >> nx.append("7") >> >> >> if y in "tuv": >> >> >> nx.append("8") >> >> >> if y in "wxyz": >> >> >> nx.append("9") >> >> >> number="".join(e for e in nx) >> >> >> return number >> >> >> a="1-800-getcharter" >> >> >> print (nametonumber(a))#1800 438 2427 837 >> >> >> a="1-800-leo laporte" >> >> >> print (nametonumber(a)) >> >> >> a="1 800 dialaho" >> >> >> print (nametonumber(a)) >> >> >> >> >> >> Please >> >> > >> >> >Your code here is actually pretty close to a correct answer. Just a few >> >> >things to consider... >> >> > >> >> >- Why are you converting your name string to a list? It is unnecessary. >> >> > When you do "for y in ", then y will still be single >> >> >characters on each iteration of the loop. >> >> > >> >> >- "if y in string.digits" should work fine. >> >> > >> >> >- "if y in list(range(1,10)" won't work for two reasons: First, it >> >> >creates a list of numbers, not strings. Second, even if it did, it >> >> >would be missing the "0" digit. >> >> > >> >> >- At the end, when you convert your list to a string, you don't need to >> >> >use list comprehension, since nx is already a list. number = >> >> >"".join(nx) should work fine. >> >> > >> >> >Also, in general, you need to stop and slow down and think like a >> >> >programmer. If you get an error, your instinct shouldn't be to just >> >> >hack at it to make the error go away. Look at the error and try to make >> >> >sense of it. Learn what the error means and try to fix the core problem. >> >> > >> >> >And for @#$%'s sake...stop saying "It isn't working" and not >> >> >elaborating. You've been told by every other post in this thread to >> >> >show us what you did and what the error was. You've also been told to >> >> >*NOT* retype what you see and to copy/paste your code and the error >> >> >because when you make a typo when copying, we might see a problem that >> >> >doesn't exist and then you just get more confused. >> >> >> >> Ok I think I may have the question you guys are looking for. >> >> I just posted it. >> >> See above. >> >> >> >> But it's still broke. :( >> > >> >str(range(10)) doesn't do
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 10:38:31 -0400, Seymore4Head wrote:
> I tried list(range(10)
This is missing a ")"
It probably sat there waiting for you to finish the line.
list(range(10))
You have two "(" in the line, you need two ")" to match them.
> I thought that would work in Python 3. It
> didn't.
It does if you enter it properly.
also try:
str(list(range(10)))
Note that that has three "(" and three ")" on the line.
--
Denis McMahon, [email protected]
--
https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
On Fri, 24 Oct 2014 10:20:30 -0700, Dan Stromberg wrote: > On Fri, Oct 24, 2014 at 1:38 AM, Steven D'Aprano > wrote: >> I don't get why that's considered hard to read. > >> So why is it hard to read when the index is a flag? >> >> value = [f, g][cond]() > > It's clear to you, it's clear to me, but is it clear to everyone? I > very much doubt it. I had to mentally step through this before it became apparent what it was doing, can see places where it could be usefull (a switch replacement) but it is not instantly obvious a = if else is instantly obvious (at least to a native English speaker anyway) > > Also, you've gone to the trouble of def'ing two functions here - you may > as well do a function for the if/else. -- "Humor is a drug which it's the fashion to abuse." -- William Gilbert -- https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
alister : > a = if else > > is instantly obvious (at least to a native English speaker anyway) And you can go further down that road. For example, you could say things like: die unless everything is OK Marko -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 20:37:31 + (UTC), Denis McMahon
wrote:
>On Fri, 24 Oct 2014 10:38:31 -0400, Seymore4Head wrote:
>
>> I tried list(range(10)
>
>This is missing a ")"
>
>It probably sat there waiting for you to finish the line.
>
>list(range(10))
>
>You have two "(" in the line, you need two ")" to match them.
>
>> I thought that would work in Python 3. It
>> didn't.
>
>It does if you enter it properly.
>
>also try:
>
>str(list(range(10)))
>
>Note that that has three "(" and three ")" on the line.
I make lots of typing mistakes. It is not that. Did you see the short
example I posted?
name="123-xyz-abc"
for x in name:
if x in range(10):
print ("Range",(x))
if x in str(range(10)):
print ("String range",(x))
It doesn't throw an error but it doesn't print what you would expect.
--
https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 16:58:00 -0400, Seymore4Head wrote:
> On Fri, 24 Oct 2014 20:37:31 + (UTC), Denis McMahon
> wrote:
>
>>On Fri, 24 Oct 2014 10:38:31 -0400, Seymore4Head wrote:
>>
>>> I tried list(range(10)
>>
>>This is missing a ")"
>>
>>It probably sat there waiting for you to finish the line.
>>
>>list(range(10))
>>
>>You have two "(" in the line, you need two ")" to match them.
>>
>>> I thought that would work in Python 3. It didn't.
>>
>>It does if you enter it properly.
>>
>>also try:
>>
>>str(list(range(10)))
>>
>>Note that that has three "(" and three ")" on the line.
>
> I make lots of typing mistakes. It is not that. Did you see the short
> example I posted?
>
> name="123-xyz-abc"
> for x in name:
> if x in range(10):
> print ("Range",(x))
> if x in str(range(10)):
> print ("String range",(x))
>
> It doesn't throw an error but it doesn't print what you would expect.
it prints what "I" expect, it probably does not print what you expect
you have may times been told that str(range(10)) does not do what you
expect but you keep failing to test
you think that it crates a list of strings ['1','2','3'] but it does
not
it creates a list & then turns the whole list into a string '[1,2,3...]'
people are suggesting you try this things in the interactive prompt
because doing teaches far better than just reading.
--
Honesty's the best policy.
-- Miguel de Cervantes
--
https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On 24/10/2014 15:47, Seymore4Head wrote: I have at least 10 ebooks. I will get around to reading them soon. Sooner would be better. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, Oct 24, 2014 at 2:58 PM, Seymore4Head
wrote:
> name="123-xyz-abc"
> for x in name:
> if x in range(10):
> print ("Range",(x))
> if x in str(range(10)):
> print ("String range",(x))
>
> It doesn't throw an error but it doesn't print what you would expect.
That prints exactly what I expect it to. The first if prints nothing,
because you're testing whether a string is contained in a sequence of
ints. That will always be false. The second if prints those characters
from name that happen to be in the string "range(10)". That's the "1"
and the "a".
Apparently it doesn't print what *you* expect, which is why you need
to make your expectation clear and not assume that we will just read
your mind and immediately understand what you expect the code to do.
--
https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 14:15:13 -0400, Seymore4Head wrote: > I do understand that. 7 is a number and "7" is a string. > What my question was...and still is...is why Python 3 fails when I try > using y=1 800 get charter > > y in range str(range(10)) > should work because y is a string and str(range(10)) should be "y" in > str(1) fails. > It doesn't give an error it's just not True when y is a number. This is because str(range(10)) does not do what you think it does. In python 2.x, str(range(10)) creates a string representation of the complete list, not a list of the string representation of the separate list elements. '[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]' In python 3.x, str(range(10)) creates a string representation of the list object. 'range(0, 10)' the only single digit strings in the python3 representation are "0" and "1" To recreate the python2 behaviour in python 3, use: str(list(range(10))) which gives '[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]' howver the test: if x.isdigit(): is much better. But finally, with your telephone number decoder, look at: http://www.codeskulptor.org/#user38_QnR06Upp4AH6h0Q.py -- Denis McMahon, [email protected] -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 21:19:22 + (UTC), Denis McMahon wrote: >On Fri, 24 Oct 2014 14:15:13 -0400, Seymore4Head wrote: > >> I do understand that. 7 is a number and "7" is a string. >> What my question was...and still is...is why Python 3 fails when I try >> using y=1 800 get charter >> >> y in range str(range(10)) >> should work because y is a string and str(range(10)) should be "y" in >> str(1) fails. >> It doesn't give an error it's just not True when y is a number. > >This is because str(range(10)) does not do what you think it does. > >In python 2.x, str(range(10)) creates a string representation of the >complete list, not a list of the string representation of the separate >list elements. '[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]' > >In python 3.x, str(range(10)) creates a string representation of the list >object. 'range(0, 10)' > >the only single digit strings in the python3 representation are "0" and >"1" > >To recreate the python2 behaviour in python 3, use: > >str(list(range(10))) > >which gives > >'[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]' > >howver the test: > >if x.isdigit(): > >is much better. > >But finally, with your telephone number decoder, look at: > >http://www.codeskulptor.org/#user38_QnR06Upp4AH6h0Q.py That is much cleaner than mine. Nice. I did make one more change to mine that makes it easier to read. I changed treating all " -()" With a space. I am still thinking about how to treat the large space if it is a digit instead: 1 800 555 -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 10:38:31 -0400, Seymore4Head wrote: > Thanks everyone for your suggestions. Try loading the following in codeskulptor: http://www.codeskulptor.org/#user38_j6kGKgeOMr_0.py -- Denis McMahon, [email protected] -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 15:07:06 -0400, Seymore4Head wrote:
> On Fri, 24 Oct 2014 19:40:39 +0100, Mark Lawrence
> wrote:
>
>>On 24/10/2014 19:20, Seymore4Head wrote:
>>> I meant to type:
>>> if y in range(1,10) doesn't work.
>>> Sigh Sorry
>>>
>>>
>>How many more times, state what you expect to happen and what actually
>>happens. "doesn't work" is useless. Please read this http://sscce.org/
>
> Good suggestion.
> OK how is this?
> It doesn't print what I expect.
> Does it print what you expect?
>
> name="123-xyz-abc"
> for x in name:
> if x in range(10):
> print ("Range",(x))
> if x in str(range(10)):
> print ("String range",(x))
>
> http://i.imgur.com/EGKUpAb.jpg
I suspect you're discovering the difference between the python2 and
python3 range() functions, and what happens when you encapsulate them in
string.
I've already posted about this once this evening.
--
Denis McMahon, [email protected]
--
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Re: I am out of trial and error again Lists
Seymore4Head Wrote in message: > On Fri, 24 Oct 2014 09:54:23 -0700 (PDT), Rustom Mody > wrote: > >>Totally befuddled myself! >> >>Are you deliberately misspelling list to lst >>and hoping the error will go away. >> >>And Puh LEESE >>dont post screen shots of good ol ASCII text > > I didn't do that on purpose. I make a lot of typing mistakes. > Sorry > That's what copy/paste are for. Copy from your console, and paste into your email. Don't ever retype unless you're trying to frustrate us, -- DaveA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 21:48:14 + (UTC), Denis McMahon wrote: >On Fri, 24 Oct 2014 10:38:31 -0400, Seymore4Head wrote: > >> Thanks everyone for your suggestions. > >Try loading the following in codeskulptor: > >http://www.codeskulptor.org/#user38_j6kGKgeOMr_0.py That is a useful way to test. Thanks. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head wrote: Thanks for all the helpful replies. I just discovered that there is something wrong with my news feed. Some of the messages did not make it to me. I can go back and read this thread in Google Groups but I can't reply to it. If I missed thanking or replying to anyone, that is the reason. Thanks again -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 18:09:59 -0400 (EDT), Dave Angel wrote: >Seymore4Head Wrote in message: >> On Fri, 24 Oct 2014 09:54:23 -0700 (PDT), Rustom Mody >> wrote: >> >>>Totally befuddled myself! >>> >>>Are you deliberately misspelling list to lst >>>and hoping the error will go away. >>> >>>And Puh LEESE >>>dont post screen shots of good ol ASCII text >> >> I didn't do that on purpose. I make a lot of typing mistakes. >> Sorry >> > >That's what copy/paste are for. Copy from your console, and paste > into your email. Don't ever retype unless you're trying to > frustrate us, I promise I am not trying to frustrate anyone. I know I have. Sorry -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head
wrote:
name="123-xyz-abc"
a=range(10)
b=list(range(10))
c=str(list(range(10)))
print ("a",(a))
print ("b",(b))
print ("c",(c))
for x in name:
if x in a:
print ("a",(x))
if x in b:
print ("b",(x))
if x in c:
print ("c",(x))
B is type list and C is type str.
I guess I am still a little too thick. I would expect b and c to
work.
http://i.imgur.com/dT3sEQq.jpg
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Re: I am out of trial and error again Lists
On Saturday, October 25, 2014 4:00:01 AM UTC+5:30, Seymore4Head wrote: > On Fri, 24 Oct 2014 18:09:59 -0400 (EDT), Dave Angel wrote: > > Don't ever retype unless you're trying to > > frustrate us, > > I promise I am not trying to frustrate anyone. I know I have. > Sorry No issues Seymore :-) As far as I am concerned this has been useful and educative for me -- I found out about codeskulptor. Though I am a bit conflicted whether it helps or confuses students. Also many other things... What I take as minor distinctions between python 2 and 3 may not be so minor if one doesn't know whats going on. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 17:35:34 -0400, Seymore4Head wrote: >>But finally, with your telephone number decoder, look at: >> >>http://www.codeskulptor.org/#user38_QnR06Upp4AH6h0Q.py > > That is much cleaner than mine. Nice. > > I did make one more change to mine that makes it easier to read. I > changed treating all " -()" With a space. > I am still thinking about how to treat the large space if it is a digit > instead: > 1 800 555 Note that my decoder assumes anything other than a letter can be copied straight to the output string. -- Denis McMahon, [email protected] -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 16:58:00 -0400, Seymore4Head wrote:
> I make lots of typing mistakes. It is not that. Did you see the short
> example I posted?
>
> name="123-xyz-abc"
> for x in name:
> if x in range(10):
> print ("Range",(x))
> if x in str(range(10)):
> print ("String range",(x))
>
> It doesn't throw an error but it doesn't print what you would expect.
It prints exactly what I expect.
Try the following:
print(str(range(10)), type(str(range(10
print(str(list(range(10))), type(str(listr(range(10)
In python 3, str(x) just wraps x up and puts it in a string. range(x)
generates an iterable range object.
hence str(range(10)) is a string telling you that range(10) is an iterable
range object with certain boundaries.
However, list(iterable) expands the iterable to the full list of possible
values, so str(list(range(10))) is a string representation of the list
containing the values that the iterable range(10) creates.
Note that whether you're looking at a string representation of a value or
the value itself is a lot clearer in the interpreter console where
strings are displayed with quotes.
--
Denis McMahon, [email protected]
--
https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On 24/10/2014 23:58, Seymore4Head wrote:
On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head
wrote:
name="123-xyz-abc"
a=range(10)
b=list(range(10))
c=str(list(range(10)))
print ("a",(a))
print ("b",(b))
print ("c",(c))
for x in name:
if x in a:
print ("a",(x))
if x in b:
print ("b",(x))
if x in c:
print ("c",(x))
B is type list and C is type str.
I guess I am still a little too thick. I would expect b and c to
work.
http://i.imgur.com/dT3sEQq.jpg
Why?
--
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.
Mark Lawrence
--
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Re: I am out of trial and error again Lists
On Saturday, October 25, 2014 4:30:47 AM UTC+5:30, Seymore4Head wrote:
> On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head wrote:
>
> name="123-xyz-abc"
> a=range(10)
> b=list(range(10))
> c=str(list(range(10)))
> print ("a",(a))
> print ("b",(b))
> print ("c",(c))
>
> for x in name:
> if x in a:
> print ("a",(x))
> if x in b:
> print ("b",(x))
> if x in c:
> print ("c",(x))
>
> B is type list and C is type str.
> I guess I am still a little too thick. I would expect b and c to
> work.
Lets simplify the problem a bit.
Do all the following in interpreter window
>>> name="012"
>>> b=list(range(3))
>>> for x in name: print x
>>> for x in b: print x
Same or different?
Now go back to Denis' nice example and put in type(x)
into each print
Same or different?
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 18:58:04 -0400, Seymore4Head wrote:
> On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head
> wrote:
OK, assuming you tried to run this in python3, not python2 or
codeskulptor.
> name="123-xyz-abc"
> a=range(10)
a is an iterable object giving the numbers 0 through 9
> b=list(range(10))
b is an list containing the numbers 0 through 9
> c=str(list(range(10)))
c is an string representation of a list containing the numbers 0
through 9
> print ("a",(a))
> print ("b",(b))
> print ("c",(c))
>
> for x in name:
^ x is a string representing one character in name
> if x in a:
> print ("a",(x))
here you are looking for a string x amongst the numbers yielded by
an iterable
> if x in b:
> print ("b",(x))
here you are comparing a string x with the elements of a list of
numbers
> if x in c:
> print ("c",(x))
here you are comparing a string x with the characters in a string
representation of a list of numbers
> B is type list and C is type str.
> I guess I am still a little too thick. I would expect b and c to work.
> http://i.imgur.com/dT3sEQq.jpg
a is the range object: range(0, 9)
b is the list: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
c is the string: "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
When you try and compare a character x eg "8" with the numbers yielded by
the iterable a, none of them match because character "8" is not the same
as number 8
When you try and compare a character x eg "8" with the elements of the
list b, none of them match because character "8" is not the same as
number 8
When you try and compare a character x eg "8" with the string
representation of the list b, you get a match of x "8" to the 25th
character of string c which is also "8".
--
Denis McMahon, [email protected]
--
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 16:27:58 -0700 (PDT), Rustom Mody
wrote:
>On Saturday, October 25, 2014 4:30:47 AM UTC+5:30, Seymore4Head wrote:
>> On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head wrote:
>>
>> name="123-xyz-abc"
>> a=range(10)
>> b=list(range(10))
>> c=str(list(range(10)))
>> print ("a",(a))
>> print ("b",(b))
>> print ("c",(c))
>>
>> for x in name:
>> if x in a:
>> print ("a",(x))
>> if x in b:
>> print ("b",(x))
>> if x in c:
>> print ("c",(x))
>>
>> B is type list and C is type str.
>> I guess I am still a little too thick. I would expect b and c to
>> work.
>
>Lets simplify the problem a bit.
>Do all the following in interpreter window
>
name="012"
b=list(range(3))
>
for x in name: print x
>
for x in b: print x
>
>Same or different?
>
>Now go back to Denis' nice example and put in type(x)
>into each print
>
>Same or different?
First. The interpreter is not good for me to use even when I am using
Python 3 because I forget to add : and I forget to put () around the
print statements.
To keep me from having to correct myself every time I use it, it is
just easier to make a short py file.
Here is mine:
name="012"
b=list(range(3))
for x in name: print (x)
print (type (x))
for x in b: print (x)
print (type (b))
I don't understand what I was supposed to learn from that. I know
that name will be a string so x will be a string.
I would still think if you compare a 1 from a string to a 1 from a
list, it should be the same.
Obviously I am wrong, but we knew that already.
I get they are not the same, but I still think they should be.
name="012"
b=list(range(3))
print (name[1])
print ([1])
1
[1]
OK I get it. They are not the same. I was expecting "1"
--
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 23:21:43 + (UTC), Denis McMahon
wrote:
>On Fri, 24 Oct 2014 16:58:00 -0400, Seymore4Head wrote:
>
>> I make lots of typing mistakes. It is not that. Did you see the short
>> example I posted?
>>
>> name="123-xyz-abc"
>> for x in name:
>> if x in range(10):
>> print ("Range",(x))
>> if x in str(range(10)):
>> print ("String range",(x))
>>
>> It doesn't throw an error but it doesn't print what you would expect.
>
>It prints exactly what I expect.
>
>Try the following:
>
>print(str(range(10)), type(str(range(10
>print(str(list(range(10))), type(str(listr(range(10)
>
>In python 3, str(x) just wraps x up and puts it in a string. range(x)
>generates an iterable range object.
>
>hence str(range(10)) is a string telling you that range(10) is an iterable
>range object with certain boundaries.
>
>However, list(iterable) expands the iterable to the full list of possible
>values, so str(list(range(10))) is a string representation of the list
>containing the values that the iterable range(10) creates.
>
>Note that whether you're looking at a string representation of a value or
>the value itself is a lot clearer in the interpreter console where
>strings are displayed with quotes.
I get it now.
Thanks
--
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 19:48:16 -0400, Seymore4Head
wrote:
>On Fri, 24 Oct 2014 16:27:58 -0700 (PDT), Rustom Mody
> wrote:
>
>>On Saturday, October 25, 2014 4:30:47 AM UTC+5:30, Seymore4Head wrote:
>>> On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head wrote:
>>>
>>> name="123-xyz-abc"
>>> a=range(10)
>>> b=list(range(10))
>>> c=str(list(range(10)))
>>> print ("a",(a))
>>> print ("b",(b))
>>> print ("c",(c))
>>>
>>> for x in name:
>>> if x in a:
>>> print ("a",(x))
>>> if x in b:
>>> print ("b",(x))
>>> if x in c:
>>> print ("c",(x))
>>>
>>> B is type list and C is type str.
>>> I guess I am still a little too thick. I would expect b and c to
>>> work.
>>
>>Lets simplify the problem a bit.
>>Do all the following in interpreter window
>>
> name="012"
> b=list(range(3))
>>
> for x in name: print x
>>
> for x in b: print x
>>
>>Same or different?
>>
>>Now go back to Denis' nice example and put in type(x)
>>into each print
>>
>>Same or different?
>
>First. The interpreter is not good for me to use even when I am using
>Python 3 because I forget to add : and I forget to put () around the
>print statements.
>
>To keep me from having to correct myself every time I use it, it is
>just easier to make a short py file.
>
>Here is mine:
>
>name="012"
>b=list(range(3))
>for x in name: print (x)
>print (type (x))
>for x in b: print (x)
>print (type (b))
>
>I don't understand what I was supposed to learn from that. I know
>that name will be a string so x will be a string.
>I would still think if you compare a 1 from a string to a 1 from a
>list, it should be the same.
>
>Obviously I am wrong, but we knew that already.
>I get they are not the same, but I still think they should be.
>
>name="012"
>b=list(range(3))
>print (name[1])
>print ([1])
>
>1
>[1]
>
>OK I get it. They are not the same. I was expecting "1"
>
Wait! I don't get it.
name="012"
b=list(range(3))
print (name[1])
print (b[1])
1
1
I forgot the b
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Re: I am out of trial and error again Lists
On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head
wrote:
name="012"
b=list(range(3))
print (name[1])
print (b[1])
if name[1] == b[1]:
print ("Eureka!")
else:
print ("OK, I get it")
--
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Re: I am out of trial and error again Lists
On 2014-10-25 00:57, Seymore4Head wrote:
[snip]
Wait! I don't get it.
name="012"
b=list(range(3))
print (name[1])
print (b[1])
1
1
I forgot the b
If you print the int 1, you'll see:
1
If you print the string "1", you'll see:
1
Normally you want it to print only the characters of the string. Think
how annoying it would be if every time you printed a string it appeared
in quotes:
>>> print("Hello world!")
'Hello world!'
How could you print just the text:
Hello world!
No, it's better that it prints the characters of the string.
One function you can use is repr:
x = 1
y = "1"
print(repr(x))
print(repr(y))
This will print:
1
'1'
OK, now it's clear that x is an int and y is a string.
--
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Re: I am out of trial and error again Lists
On 10/24/2014 6:27 PM, Seymore4Head wrote: I promise I am not trying to frustrate anyone. I know I have. Seymore, if you want to learn real Python, download and install 3.4.2 and either use the Idle Shell and Editor or the interactive console interpreter and a decent programmer editor. I cannot recommend CodeSkulptor to anyone. The opening statement # CodeSkulptor runs Python programs is deceptive. CodeSkulptor Python is not Python. It does not correspond to any x.y version of Python. It is a somewhat crippled subset of ancient Python (2.1) with selected additions of later features. It does not have exceptions, raise, and try: except:. These are an essential part of original Python and Python today It does not have complex (maybe introduced in 1.5) and unicode (introduced in 2.0). Let that pass. More important, it does not have new-style classes, an essential new feature introduced in 2.2. Python beginners should start with unified new-styled classes. If lucky, they need never learn about the original old style, dis-unified type versus class system that started going away in 2.2, is mostly gone in 2.7. and completely gone in 3.0. If you really want to continue with CodeSkulpter Python, you should find a CodeSkulpterPython list. You cannot expect people here to know that legal code like class I(int): pass will not run, but will fail with an exceeding cryptic message: Line 1: undefined: TypeError: a.$d is undefined Nor can you expect us to know all the other limitations. This is a list for Python. If you want help here, get and use a real Python interpreter, with a proper interactive mode, as multiple people have suggested. -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, 25 Oct 2014 01:20:53 +0100, MRAB
wrote:
>On 2014-10-25 00:57, Seymore4Head wrote:
>[snip]
>> Wait! I don't get it.
>> name="012"
>> b=list(range(3))
>> print (name[1])
>> print (b[1])
>> 1
>> 1
>>
>> I forgot the b
>>
>If you print the int 1, you'll see:
>
>1
>
>If you print the string "1", you'll see:
>
>1
>
>Normally you want it to print only the characters of the string. Think
>how annoying it would be if every time you printed a string it appeared
>in quotes:
>
> >>> print("Hello world!")
>'Hello world!'
>
>How could you print just the text:
>
>Hello world!
>
>No, it's better that it prints the characters of the string.
>
>One function you can use is repr:
>
>x = 1
>y = "1"
>print(repr(x))
>print(repr(y))
>
>This will print:
>
>1
>'1'
>
>OK, now it's clear that x is an int and y is a string.
Yes
x = 123
y = "123"
z = [1,2,3]
print(repr(x))
print(repr(y))
print(repr(z))
123
'123'
[1, 2, 3]
Thanks
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Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 20:27:03 -0400, Terry Reedy wrote: >On 10/24/2014 6:27 PM, Seymore4Head wrote: > >> I promise I am not trying to frustrate anyone. I know I have. > >Seymore, if you want to learn real Python, download and install 3.4.2 >and either use the Idle Shell and Editor or the interactive console >interpreter and a decent programmer editor. > >I cannot recommend CodeSkulptor to anyone. The opening statement ># CodeSkulptor runs Python programs >is deceptive. CodeSkulptor Python is not Python. It does not correspond >to any x.y version of Python. It is a somewhat crippled subset of >ancient Python (2.1) with selected additions of later features. It does >not have exceptions, raise, and try: except:. These are an essential >part of original Python and Python today It does not have complex >(maybe introduced in 1.5) and unicode (introduced in 2.0). Let that >pass. More important, it does not have new-style classes, an essential >new feature introduced in 2.2. Python beginners should start with >unified new-styled classes. If lucky, they need never learn about the >original old style, dis-unified type versus class system that started >going away in 2.2, is mostly gone in 2.7. and completely gone in 3.0. > >If you really want to continue with CodeSkulpter Python, you should find >a CodeSkulpterPython list. You cannot expect people here to know that >legal code like > class I(int): pass >will not run, but will fail with an exceeding cryptic message: > Line 1: undefined: TypeError: a.$d is undefined >Nor can you expect us to know all the other limitations. > >This is a list for Python. If you want help here, get and use a real >Python interpreter, with a proper interactive mode, as multiple people >have suggested. OK. I will. Thanks But the difference between Python 2 and Codeskulptor was not an issue with this question. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On 24Oct2014 20:37, Seymore4Head wrote: On Sat, 25 Oct 2014 01:20:53 +0100, MRAB One function you can use is repr: x = 1 y = "1" print(repr(x)) print(repr(y)) This will print: 1 '1' OK, now it's clear that x is an int and y is a string. Yes In particular, Python's interactive mode uses repr to print the result of any expression that whose value was not None: [/Users/cameron]fleet*> python Python 2.7.8 (default, Oct 3 2014, 02:34:26) [GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> x=1 >>> y='1' >>> x 1 >>> y '1' >>> so you get this for free in that mode. Cheers, Cameron Simpson If your new theorem can be stated with great simplicity, then there will exist a pathological exception.- Adrian Mathesis -- https://mail.python.org/mailman/listinfo/python-list
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python student at university of jordan.
Hi,
my name is heba ibrahim abukaff from jordan ,iam a computer information system
student at university of jordan .
i have a trouble using the tokenizer to find the frequency list for URL using
arabic text.and iam using python 2.7.2 on winXP,I tried this code but every
time i run the code appears error with first line
COULD YOU HELP ME.
WITH REGARDS.
::
python 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)] on
win32
> import re, codecs
import nltk
from urllib import request
url = "http://ar.wikipedia.org/wiki/%D9%85%D9%88%D9%82%D8%B9_%D9%88%D9%8A%D8%A8";
response = request.urlopen(url)
raw = response.read().decode('utf8')
print(raw)
import re, codecs import nltk from nltk.probability
import * def construct_frequency_list(words):
outfile = codecs.open(r'raw.txt' , 'w')
fd = nltk.probability.FreqDist()
for w in words: fd.inc(w)
print "Total number of words: %d Vocbulary size : %d" % (fd.N(), fd.B())
print "word with highest count: %s" % (fd.max())
tokenlist = fd.iteritems()
for (key, value) in tokenlist:
print>>outfile, "%s\t%d" % (key, value)
outfile.close() def read_textfile(raw ):
lines = codecs.open(raw ,'r','utf_8').readlines()
outfile = codecs.open(r'raw.txt' ,'w','utf_8')
counter = 0 wordlist = [] for line in lines:
tokens = line.rstrip().lstrip().split()
for t in tokens: wordlist.append(t)
print>>outfile, '%s\t%d' % (t, len(t))
counter += len(t) outfile.close()
return wordlist if __name__ == "__main__":
words = read_textfile(r'raw .txt')
construct_frequency_list(words)
print "Done!"
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Re: python student at university of jordan.
On Sat, Oct 25, 2014 at 12:47 PM, heba abukaff
wrote:
> i have a trouble using the tokenizer to find the frequency list for URL using
> arabic text.and iam using python 2.7.2 on winXP,I tried this code but every
> time i run the code appears error with first line
I'm seeing two problems here. One of them may not actually be a
problem in your code, but just in how you're posting: your text has
all been rewrapped. Post the exact code, as plain text (not HTML); you
should be able to do this, but if you can't with Yahoo, try a
different email provider. Make sure we can see exactly where your code
begins and ends, so we can understand what "first line" you're looking
at - and if you copy and paste the actual error you get, that would be
extremely helpful, too. (Even if it's in Arabic. There'll be parts we
can understand.)
The second problem is that you're trying to work with non-English text
in Python 2.7. This is harder than it needs to be. Install the latest
Python (3.4) and use that instead of 2.7; the NLTK module is
compatible with 3.2+, so it should work fine. I can't be sure that
you're having trouble with bytes vs strings, because I can't see what
your code's doing (due to the wrap/indent problem), but in any case,
shifting to Python 3 gives you a much better chance of getting things
right. All you'll need to do, I suspect, is change your print
statements into function calls:
# Old style:
print "word with highest count: %s" % (fd.max())
# New style:
print("word with highest count: %s" % (fd.max()))
Easy! And only slightly harder when you send it to a different destination:
# Old style:
print>>outfile, '%s\t%d' % (t, len(t))
# New style:
print('%s\t%d' % (t, len(t)), file=outfile)
With those changes, your code will probably (I can't test it) work on
Python 3.4.
ChrisA
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Re: I am out of trial and error again Lists
On 10/24/2014 07:38 AM, Seymore4Head wrote: I do get the difference. I don't actually use Python 2. I use CodeSkulptor. I do have Python 3 installed. Actually I have Python 2 installed but IDLE defaults to Python 3. So it is a pain to actually load Python 2. Exactly HOW are you trying to run Idle? A default install of Py2 and Py3 in Windows should have also installed Idle for each version. In my Win7 system, they are BOTH in the standard menu, you should be able to call up either one. OT: Side comment: I rarely use Windows these days, maybe once every two or three months -- I MUCH prefer Linux. Among other reasons its a far better environment for programming. I only have one (active) system with Windows installed, and two others with Linux only. Actually make that three, if you count my Raspberry Pi. :-) -=- Larry -=- -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Fri, 24 Oct 2014 19:16:21 -0700, Larry Hudson wrote: >On 10/24/2014 07:38 AM, Seymore4Head wrote: > >> I do get the difference. I don't actually use Python 2. I use >> CodeSkulptor. I do have Python 3 installed. Actually I have Python 2 >> installed but IDLE defaults to Python 3. So it is a pain to actually >> load Python 2. >> > >Exactly HOW are you trying to run Idle? A default install of Py2 and Py3 in >Windows should have >also installed Idle for each version. In my Win7 system, they are BOTH in the >standard menu, >you should be able to call up either one. > >OT: Side comment: I rarely use Windows these days, maybe once every two or >three months -- I >MUCH prefer Linux. Among other reasons its a far better environment for >programming. I only >have one (active) system with Windows installed, and two others with Linux >only. Actually make >that three, if you count my Raspberry Pi. :-) > > -=- Larry -=- I have a directory of my py files. I right click on one of the py files and "open with IDLE" Windows XP If I try to open a py file I have for Python 2 it still opens using IDLE 3. I don't have many py 2 files anyway. -- https://mail.python.org/mailman/listinfo/python-list
Re: python student at university of jordan.
On 25Oct2014 13:06, Chris Angelico wrote: On Sat, Oct 25, 2014 at 12:47 PM, heba abukaff wrote: i have a trouble using the tokenizer to find the frequency list for URL using arabic text.and iam using python 2.7.2 on winXP,I tried this code but every time i run the code appears error with first line I'm seeing two problems here. One of them may not actually be a problem in your code, but just in how you're posting: your text has all been rewrapped. Post the exact code, as plain text (not HTML); you should be able to do this, but if you can't with Yahoo, try a different email provider. Looking at his post via python-list, he _did_ post in plain text. There's no HTML at all. Make sure we can see exactly where your code begins and ends, so we can understand what "first line" you're looking at - and if you copy and paste the actual error you get, that would be extremely helpful, too. (Even if it's in Arabic. There'll be parts we can understand.) This, OTOH, yes. Heba, could you post the error message please? The complete message, including the stack trace lines if any. Cheers, Cameron Simpson -- https://mail.python.org/mailman/listinfo/python-list
Re: python student at university of jordan.
On Sat, Oct 25, 2014 at 2:05 PM, Cameron Simpson wrote: >> I'm seeing two problems here. One of them may not actually be a >> problem in your code, but just in how you're posting: your text has >> all been rewrapped. Post the exact code, as plain text (not HTML); you >> should be able to do this, but if you can't with Yahoo, try a >> different email provider. > > > Looking at his post via python-list, he _did_ post in plain text. There's no > HTML at all. Plain text is all that got through to us, but I suspect that possibly he had an HTML version that got stripped somewhere along the way. Either that, or the code that we're looking at really is what's in his .py file, in which case the first line is the version marker - no wonder it's failing. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Saturday, October 25, 2014 5:21:01 AM UTC+5:30, Seymore4Head wrote:
> On Fri, 24 Oct 2014 16:27:58 -0700 (PDT), Rustom Mody wrote:
>
> >On Saturday, October 25, 2014 4:30:47 AM UTC+5:30, Seymore4Head wrote:
> >> On Wed, 22 Oct 2014 16:30:37 -0400, Seymore4Head wrote:
> >>
> >> name="123-xyz-abc"
> >> a=range(10)
> >> b=list(range(10))
> >> c=str(list(range(10)))
> >> print ("a",(a))
> >> print ("b",(b))
> >> print ("c",(c))
> >>
> >> for x in name:
> >> if x in a:
> >> print ("a",(x))
> >> if x in b:
> >> print ("b",(x))
> >> if x in c:
> >> print ("c",(x))
> >>
> >> B is type list and C is type str.
> >> I guess I am still a little too thick. I would expect b and c to
> >> work.
> >
> >Lets simplify the problem a bit.
> >Do all the following in interpreter window
> >
> name="012"
> b=list(range(3))
> >
> for x in name: print x
> >
> for x in b: print x
> >
> >Same or different?
> >
> >Now go back to Denis' nice example and put in type(x)
> >into each print
> >
> >Same or different?
>
> First. The interpreter is not good for me to use even when I am using
> Python 3 because I forget to add : and I forget to put () around the
> print statements.
>
What would you say to a person who
- Buys a Lambhorgini
- Hitches a horse (or bullock) to it
- Moans how clumsily slow it is.
??
In case you dont get it:
- the interpreter is one of the factors that puts python into the hi-end class.
- the bullock/horse class is the C/Java type language where you always
need to work through files
Here is my list of points of sliding for bullock category to Lambhorgini:
http://blog.languager.org/2012/10/functional-programming-lost-booty.html
['Interpreter' is called 'REPL' there]
> To keep me from having to correct myself every time I use it, it is
> just easier to make a short py file.
Yes the intention is right, The implementation is wrong.
Programmers consider it a virtue to be lazy.
But you have to put it some work to learn to be lazy in an effective way
And currently you are being lazy on the wrong front.
Hints:
1. A good programmer tries out things at the interpreter ONE LINE AT A TIME
2. What he tries out are usually EXPRESSIONS like eg
str(list(range(10)))
And not STATEMENTS like
if x in name:
print x
3. IOW a good programmer rarely needs to type a colon at the interpreter
4. The least useful statement to try at the interpreter is print.
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Re: I am out of trial and error again Lists
On Saturday, October 25, 2014 9:17:12 AM UTC+5:30, Rustom Mody wrote: > 4. The least useful statement to try at the interpreter is print. Yeah this is python2 thinking; in python 3, print is technically an expression. -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
Rustom Mody writes: > On Saturday, October 25, 2014 9:17:12 AM UTC+5:30, Rustom Mody wrote: > > 4. The least useful statement to try at the interpreter is print. > > Yeah this is python2 thinking; in python 3, print is technically an > expression. This is wrong thinking. In Python 3, print is a function. -- \ “[W]hoever is able to make you absurd is able to make you | `\unjust.” —Voltaire | _o__) | Ben Finney -- https://mail.python.org/mailman/listinfo/python-list
Re: python student at university of jordan.
heba abukaff wrote: > Hi, > my name is heba ibrahim abukaff from jordan ,iam a computer information > system student at university of jordan . i have a trouble using the > tokenizer to find the frequency list for URL using arabic text.and iam > using python 2.7.2 on winXP,I tried this code but every time i run the > code appears error with first line COULD YOU HELP ME. We can only help you if you help us. We cannot guess the error that you get, you have to show us. Copy and paste the complete error message, starting from the word "Traceback" to the end. Given the code you showed: [quote] > import re, codecs import nltk [end quote] Notice the greater-than sign > at the beginning of the "import re, codecs" line? If that greater-than sign is actually in your program, you would get a syntax error: py> > import re, codecs File "", line 1 > import re, codecs ^ SyntaxError: invalid syntax If that is not the error message you are getting, you will need to tell us what error you actually are getting. Regards, -- Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: (test) ? a:b
alister wrote:
> On Fri, 24 Oct 2014 10:20:30 -0700, Dan Stromberg wrote:
>
>> On Fri, Oct 24, 2014 at 1:38 AM, Steven D'Aprano
>> wrote:
>>> I don't get why that's considered hard to read.
>>
>>> So why is it hard to read when the index is a flag?
>>>
>>> value = [f, g][cond]()
>>
[Dan]
>> It's clear to you, it's clear to me, but is it clear to everyone? I
>> very much doubt it.
Of course it won't be clear to *everyone* but it should be clear enough to
people who are familiar with standard Python idioms. A concrete example
should be more obvious than the fake example:
title = ('Mr', 'Ms')[person.sex == 'F']
which should be clear to anyone who understands indexing in Python and that
True == 1 and False == 0.
Although that's probably better written as a dict lookup:
title = {'M': 'Mr', 'F': 'Ms'}[person.sex]
which is then more easily extended to support intersex and
non-traditional[1] gender identities. Better still is to allow the
individual to choose their own title (Dr, Prof, Mrs, Miss, Mx, Sir, Dame,
etc.) rather than calculate it from their sex, but that's moving away from
the point I am making that this idiom isn't some weird and hackish
bizarrity. We use list indexing and key lookup all the time, this is just a
special case of the same. It's no more hackish than:
mapping = {True: "something which is factual",
False: "something which people prefer to believe"}
value = mapping[flag]
[Alister]
> I had to mentally step through this before it became apparent what it was
> doing, can see places where it could be usefull (a switch replacement)
> but it is not instantly obvious
Very little code is instantly obvious. Even when you know what the syntax
means, you still have to understand the semantics, and sometimes that's far
from obvious.
> a = if else
>
> is instantly obvious (at least to a native English speaker anyway)
Ha! And yet people have, and continue to, complain *bitterly* about the
non-standard ordering of Python's ternary if, compared to C, standard
if...else syntax, and English.
"If the syntax is like C, then people will use it, or else they will
complain that the syntax is incomprehensible."
Personally, I don't accept or agree with such complaints. Python's ternary
if follows the same syntax as this English variant:
"People will use it if the syntax is like C, or else they will complain that
the syntax is incomprehensible."
Still, English-like though it is, Python's ternary if does violate the
expectations of those who expect the condition to come first, as the
standard if...else block does.
[Dan]
>> Also, you've gone to the trouble of def'ing two functions here - you may
>> as well do a function for the if/else.
Not every one-liner expression needs to go into a function.
[1] For Western Christian definitions of traditional. Other cultures have
traditionally recognised more than just a binary state of gender and
sexuality, e.g. https://en.wikipedia.org/wiki/Hijra_%28South_Asia%29
--
Steven
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Re: (test) ? a:b
On Sat, Oct 25, 2014 at 4:03 PM, Steven D'Aprano wrote: > Ha! And yet people have, and continue to, complain *bitterly* about the > non-standard ordering of Python's ternary if, compared to C, standard > if...else syntax, and English. > > "If the syntax is like C, then people will use it, or else they will > complain that the syntax is incomprehensible." > > Personally, I don't accept or agree with such complaints. Python's ternary > if follows the same syntax as this English variant: > > "People will use it if the syntax is like C, or else they will complain that > the syntax is incomprehensible." Partly, I think this is a difference between programming and pure mathematics. In algebra, there's operator precedence, but no order of evaluation; in programming, there's both: https://docs.python.org/3/reference/expressions.html#evaluation-order In English, there's not really a concept of order of evaluation either. "People will use it" doesn't need to be evaluated separately from "if the syntax is like C". But in Python, the if/else operator mucks up the general principle that an expression will be evaluated left-to-right, because it's evaluated middle-to-outer for that one operator. Messing with internal expectations, even if it's following some external logic like English grammar, will confuse people. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Saturday, October 25, 2014 9:56:02 AM UTC+5:30, Ben Finney wrote: > Rustom Mody writes: > > > On Saturday, October 25, 2014 9:17:12 AM UTC+5:30, Rustom Mody wrote: > > > 4. The least useful statement to try at the interpreter is print. > > > > Yeah this is python2 thinking; in python 3, print is technically an > > expression. > > This is wrong thinking. In Python 3, print is a function. [tl;dr at bottom] Ok I was a bit sloppy -- should have said 'the print' But there was no specific prior use that 'the' would refer to. So one could say (if you like!): | | Python 2 | Python 3 | | print| syntax| function | | print(x) | statement | expression | I was really talking of the second row not the first So much for being legalistic -- An approach which is ultimately not helpful. For one thing function is one kind of expression ie its a subset not a disjoint relation. More important (in this case) its bad pedagogy. Its generally accepted that side-effecting functions are not a good idea -- typically a function that returns something and changes global state. In that sense its best to think of print(x) as syntactically an expression, semantically a statement. Or put differently, the following error is more poorly reported in python3 than in python2 Python 2.7.8 (default, Oct 7 2014, 17:59:21) [GCC 4.9.1] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> 2 + (print 2) File "", line 1 2 + (print 2) ^ SyntaxError: invalid syntax Python 3.4.2 (default, Oct 8 2014, 10:45:20) [GCC 4.9.1] on linux Type "help", "copyright", "credits" or "license" for more information. >>> 2 + (print (2)) 2 Traceback (most recent call last): File "", line 1, in TypeError: unsupported operand type(s) for +: 'int' and 'NoneType' = tl;dr I dont think all this is very helpful to Seymore -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Sat, Oct 25, 2014 at 4:40 PM, Rustom Mody wrote: > Its generally accepted that side-effecting functions are not a good idea > -- typically a function that returns something and changes global state. Only in certain circles. Not in Python. There are large numbers of functions with side effects (mutator methods like list.append, anything that needs lots of state like random.random, everything with external effect like I/O, heaps of stuff), and it is most definitely not frowned upon. In Python 3 (or Python 2 with the future directive), print is a function, print() an expression. It's not "semantically a statement". ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: I am out of trial and error again Lists
On Saturday, October 25, 2014 11:20:03 AM UTC+5:30, Chris Angelico wrote: > On Sat, Oct 25, 2014 at 4:40 PM, Rustom Mody wrote: > > Its generally accepted that side-effecting functions are not a good idea > > -- typically a function that returns something and changes global state. > > Only in certain circles. Not in Python. There are large numbers of > functions with side effects (mutator methods like list.append, > anything that needs lots of state like random.random, everything with > external effect like I/O, heaps of stuff), and it is most definitely > not frowned upon. > > In Python 3 (or Python 2 with the future directive), print is a > function, print() an expression. It's not "semantically a statement". Ok So give me a valid (ie useful) use where instead of the usual l=[1,2,3] l.append(4) we have foo(l.append(4)) -- https://mail.python.org/mailman/listinfo/python-list
