Re: [Tutor] What's in a name?
Below you will find the full current version of my Chutes or Snakes &
Ladders game. I tried to reorganize it into a more OOP structure, and I
think I started succeeding, and then something might have gone wrong. There
is also something somewhat seriously wrong with it: if I run it as
__main__, it works fine, but if I run it after I've loaded it (by
candl(100) at the prompt, for example), it is way off: something isn't
being reset, and I'm sure it'd be obvious to someone, and I'm going to look
back at it, but I can't figure it out yet. Anyway, thanks for all the help
so far, I'll probably add persistence, maybe trivial GUI, and definitely
more stats/analysis (well, almost definitely)...
""" Chutes & Ladders Simulation
Simulates a number of games of Chutes & Ladders (Snakes & Ladders).
Chutes & Ladders are separate dictionaries to allow tracking of
separate stats.
Gathers the results into a list of lists of individual game results
in the form (per game) of [game_no, moves, len(chutes), len(ladders),
[chutes], [ladders]]
There is some info redundancy in the list with the len members:
[chutes] and [ladders]
are lists of the actual chutes and ladders encountered in each game
(named by key)
"""
import random
from timer2 import timer
from statistics import * # from whence comes mean, variance, stdev
# Landing on a chute causes one to slide down to the corresponding value.
chutes = {16: 6, 47: 26, 49: 11, 56: 53, 62: 19, 64: 60, 87: 24, 93: 73,
95: 75, 98:78}
# Landing on a ladder (key) causes one to climb up to the corresponding
value.
ladders = {1: 38, 4: 14, 9: 31, 21: 42, 28: 84, 36: 44, 51: 67, 71: 91,
80:100}
class games:
"""Game class for Chutes & Ladders."""
def __init__(self):
self.reset()
def reset(self):
self.move_count = 0
self.num_chutes = 0
self.num_ladders = 0
self.chutes_list = []
self.ladders_list = []
#@timer
def move(self):
"""Single move, with chutes, ladders, & out of bounds.
Primary action is to move self.position, but returns a list
that consists of either the chute or ladder if landed on, if either
"""
roll = random.randint(1,6)
tchutes = 0
tladders = 0
self.move_count += 1
self.position += roll
if self.position in chutes:
tchutes = self.position
self.position = chutes[self.position]
self.num_chutes += 1
elif self.position in ladders:
tladders = self.position
self.position = ladders[self.position]
self.num_ladders += 1
elif self.position > 100: # move doesn't count, have to land
exactly
self.position -= roll
return [tchutes, tladders] # only one will be != 0
#@timer
def play_game(self, step):
"""Single game"""
self.position = 0
self.reset()
while self.position < 100:
gamecandl = self.move() # [chute, ladder] or [0, 0]
if gamecandl[0] != 0: # populate chutes list
self.chutes_list.append(gamecandl[0])
if gamecandl[1] != 0: # populate ladders list
self.ladders_list.append(gamecandl[1])
return [step, self.move_count, self.num_chutes, self.num_ladders,
self.chutes_list, self.ladders_list]
#@timer
def play_gameset(self, gamecount1):
"""A set of games, returning associated stats array"""
return [self.play_game(i) for i in range(gamecount1)]
def candl(gamecount2):
""" play a mess of games, return the results array """
gname = games()
game_array = gname.play_gameset(gamecount2)
print_gameset_stats(game_array)
print_candl_info(game_array)
#print(game_array)
def print_gameset_stats(garray):
print("Total number of games: ", len(garray))
print(" MovesChutesLadders")
for func in [mean, max, min, variance, stdev]:
print("{moves:9.2f} {chutes:12.2f} {ladders:13.2f}
{stype}".format(
moves=func(tgset[1] for tgset in garray),
chutes=func(tgset[2] for tgset in garray),
ladders=func(tgset[3] for tgset in garray),
stype=func.__name__
))
def timing_report():
print("game.total, count = ", p1.game.total, p1.game.count)
print("move.total, count = ", p1.move.total, p1.move.count)
def print_candl_info(garray):
""" Create two dictionaries with the same keys as chutes & ladders,
but with the total number of times each c or l is traversed (in the
entire gameset)
as the values. Then, print them. """
chute_nums, ladder_nums = chutes, ladders
summarize_game("chutes", chutes, 4, garray)
summarize_game("ladders", ladders, 5, garray)
def summarize_game(game_name, game_nums, game_index, garray):
for i in game_nums.keys(): game_nums[i] = 0
for corl in game_nums:
for game in garray:
i
Re: [Tutor] What's in a name?
On Fri, Jan 3, 2014 at 2:42 AM, Danny Yoo wrote:
>
> I hope you don't take offense. But I actually do not understand
> print_candl_info(). I thought I did! But then I realized I was
> deluding myself. I don't not understand it after all, and that's
> after staring at it for more than about thirty minutes.
>
>
I dare you to try to offend me, while offering helpful comments! Okay, I
take that back. Anyway, no I don't.
> Take that a "canary in the coalmine" kind of comment. eval() can
> encourages habits that hurt program readability in a deep way.
>
> Fair enough.
> where we first unroll the original's outer loop out so that there are
> no eval()s anywhere. This hurts program length a little, but we can
> deal with that. Do you agree so far that the program above preserves
> the meaning of what you had before?
>
>
Ha ha, you must understand, because you recreated the original form of the
code. First, realize that this is all a learning exercise for me, I am not
actually obsessed by Chutes & Ladders. So I was trying to figure out if I
could do this thing of iterating over a list of (functions, lists,
dictionaries) and print both some output related to the object, and the
objects name. But I think you now understand that. In this _particular_
case, I've got that little list_index kluge, which is probably good, since
it sort of forces me to try to solve a more general case (or get other
people to!... er, thanks!)
>
> If we can assume that the rewritten code "means" the same thing, then
> we can eliminate the duplication by doing something like this:
>
>
> def print_candl_info(garray):
> game_array, chute_nums, ladder_nums = {}, chutes, ladders
> for i in chute_nums.keys(): chute_nums[i] = 0
> for i in ladder_nums.keys(): ladder_nums[i] = 0
>
> summarize_game("chutes", chute_nums, 4, garray)
> summarize_game("ladders", ladder_nums, 5, garray)
>
>
I see what you did there.
> Hmmm. I don't understand why chute_nums is assigned to chutes, nor
> ladder_nums to ladders, and I don't see game_array being used here
> yet. We can absorb that:
>
>
>
Yes, game_array was left over, sorry. But chutes and ladders are
dictionaries that should remain unchanged, for the purpose of future games.
chute_nums = chutes only b/c that was an easy way to fill in all the keys:
I then zero out the values, and increment the values for every time any
given chute or ladder is traversed during a game (this information is in
game[4] and game[5], each of which are lists of the chutes or ladders
traversed in each given game). I hope that's clear. So I think you can't
lose that, or you'd have to fill in those keys differently (which is how I
did it at first, but this approach seemed cleaner).
> def print_candl_info(garray):
> summarize_game("chutes", chutes, 4, garray)
> summarize_game("ladders", ladders, 5, garray)
>
> def summarize_game(game_name, game_nums, game_index, garray):
> for i in game_nums.keys(): game_nums[i] = 0
>
> for corl in game_nums:
> for game in garray:
> if corl in game[game_index]:
> game_nums[corl] += 1
> print("total ", game_name, "= ", sum(game_nums.values()))
>
>
>
This is definitely an improvement, IMO. Summarize_game is _almost_ a really
good name, but it isn't really summarizing a single game: it's iterating
over all the games in garray (the array of games), and adding up all the
particular chutes and ladders occurrences, if I haven't already made that
clear... It's sneaky like that. I'm tempted to say summarize_candl, but
candl is getting boring... I'll leave it for now.
> As a side note: the code above has more latitude than the original
> because it can print out a friendlier game name. That is, for
> example, you can do this:
>
> ##
> summarize_game(" Chutes! ", chutes, 4, garray)
> summarize_game(" Ladders! ", ladders, 5, garray)
> ##
>
Yep, true that.
Thanks Danny, this was instructive. Very kind of you.
--
Keith
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Re: [Tutor] Fwd: What's in a name?
On Fri, Jan 03, 2014 at 02:45:04AM -0500, Keith Winston wrote:
> And to beat that poor horse in the same example, my current way of doing
> that would be:
>
> for alist in "lista", "listb":
> print(alist, eval(alist))
Since you know both pieces, namely the name of the entity "alist" and its
actual symbol aka alist, why not do something like:
Lists = {"lista": lista, "listb": lisb}
and use
Lists[x] ...
HTH
Asokan Pichai
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Re: [Tutor] What's in a name?
> it works fine, but if I run it after I've loaded it (by candl(100) at the
> prompt, for example), it is way off: something isn't being reset, and I'm
> sure it'd be obvious to someone,
It's due to global variable mutation. Note that summarize_game()
mutates game_nums, which is either chutes or ladders. Basically, it
writes all over the structure of the game board, which means
subsequent play throughs are a wash. :P
And you know this, from your comment:
> Yes, game_array was left over, sorry. But chutes and ladders are
> dictionaries that should remain unchanged, for the purpose of
> future games.
But to be fair, this problem was also present in the original version
of the code, before my meddling.
This is relatively straightforward to fix: just modify summarize_game
so it creates a fresh dictionary mimicking the key structure of the
entry points. That way, it doesn't mess with chutes and ladders.
##
def summarize_game(game_name, game_map, game_index, garray):
game_nums = {}
for i in game_map.keys(): game_nums[i] = 0
for corl in game_nums:
for game in garray:
if corl in game[game_index]:
game_nums[corl] += 1
print("total ", game_name, "= ", sum(game_nums.values()))
##
In the context of the full program, I now understand why you have "4"
and "5" as mysterious constants now. Good. It's due to the structure
of the return value of games.play_game().
#
return [step, self.move_count, self.num_chutes, self.num_ladders,
self.chutes_list, self.ladders_list]
#
That is, this awkwardness of indexing by number to get at chutes_list
and ladders_list is due to that result wanting not to be in a
homogenous list or sequence. The return value there *really* wants to
be something more like a dictionary or object instead.
Don't have time at the moment to sketch more than that; must sleep so
I can work tomorrow. :P
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Re: [Tutor] What's in a name?
Quick thing. Please look at the following small program:
#
d1 = {1 : 'one'}
d2 = d1
d2[2] = 'two'
print(d1)
print(d2)
#
Predict what this prints out. Write your prediction on a piece of paper.
Then run the program. Does it match what you wrote?
If not, start asking questions. If so, then I'm puzzled. :P
The reason I ask is because of the comment:
> But chutes and ladders are dictionaries that should remain
> unchanged, for the purpose of future games.
which has several meanings that I did not anticipate. So I need to
make sure you're ok on all those things. :P
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[Tutor] Mastering the fundamentals
Hello Tutorians, I've just recently acquired "Learning Python", and I must state that it is a fairly thorough book. However it seems as if I am learning at a very slow pace, so my question is, as far as setting a goal to master the basics, where should I be within a years time? Assuming I spend at least 2 hours of actual coding time per day. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sqlite3 import problem
On 03/01/14 02:17, Matthew Ngaha wrote: im having problems importing sqlite3 on ubuntu python3. File "/usr/local/lib/python3.3/sqlite3/__init__.py", line 23, in from sqlite3.dbapi2 import * File "/usr/local/lib/python3.3/sqlite3/dbapi2.py", line 26, in from _sqlite3 import * ImportError: No module named '_sqlite3' As a matter of interest why do you have the underscore in front of sqlite3? Is that deliberate? I normally import it with just import sqlite3 or from sqlite3 import ... -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
On 03/01/14 08:37, Keith Winston wrote: Below you will find the full current version of my Chutes or Snakes & Ladders game. I tried to reorganize it into a more OOP structure, This is off topic but a couple of points about the OOP stuff... Its normal style to name classes with a capital letter so it would be Games not games. It's also better to name classes as a singular. They create a single object not many so it would really be Game not Games. Finally the class name should be specific to what the class is. You class is not a generic game class its very specifically a ChutesAndLadders game class. So a better name is class ChutesAndLadders:... Finally, one comment that is more apropos to the current thread. You started by saying: "If I'm iterating a variable through a series of list names, for future processing, I would like to print the name of the list the variable is set to in a given moment... " Remember that variables in Python are just names. So we can rewrite your statement as "If I'm iterating a name through a series of list names, for future processing, I would like to print the name of the list the name is set to in a given moment... " And since the list names are just strings we can write: "If I'm iterating a name through a list of strings, for future processing, I would like to print the name in a given moment... So the answer to your question is just to print the string. The real challenge, as we have discovered, is how to access the list that is named by the string. And the usual way to map strings to objects is via a dictionary not by using eval(). Which kind of takes us back to where we were... class games: """Game class for Chutes & Ladders.""" def __init__(self): self.reset() def reset(self): self.move_count = 0 self.num_chutes = 0 self.num_ladders = 0 self.chutes_list = [] self.ladders_list = [] Do you really need the num_xxx variables? Using len(xxx_list) is more reliable that depending on your code to maintain the values. It may be that you need them for a performance optimisation but given that games are not normally CPU bound that seems unlikely. Or does num_xxx indicate something different? Looking briefly at the move() code it may be they represent the number of xxx encountered during the game? def move(self): """Single move, with chutes, ladders, & out of bounds. Primary action is to move self.position, but returns a list that consists of either the chute or ladder if landed on, if either """ roll = random.randint(1,6) tchutes = 0 tladders = 0 self.move_count += 1 self.position += roll if self.position in chutes: tchutes = self.position self.position = chutes[self.position] self.num_chutes += 1 elif self.position in ladders: tladders = self.position self.position = ladders[self.position] self.num_ladders += 1 elif self.position > 100: # move doesn't count, have to land exactly self.position -= roll return [tchutes, tladders] # only one will be != 0 I don't understand the tchutes/tladders stuff? They hold the target position or zero (the return comment is wrong BTW since both could be zero). Why not just have a single variable called target or somesuch? Also if you must return two values its probably better to use a tuple rather than a list. def play_game(self, step): """Single game""" Since this is part of a games/Game/ChutesAndLadders class you probably don't need the '_game' bit of the name, it doesn't convey any extra information. Just a thought... self.position = 0 self.reset() Shouldn't the self.position assignment be part of reset()? while self.position < 100: gamecandl = self.move() # [chute, ladder] or [0, 0] if gamecandl[0] != 0: # populate chutes list self.chutes_list.append(gamecandl[0]) if gamecandl[1] != 0: # populate ladders list self.ladders_list.append(gamecandl[1]) Why don't you do this update of the lists in the move() code. It's where it logically happens and saves passing back the list/tuple and then having to test it here. This just adds extra work. return [step, self.move_count, self.num_chutes, self.num_ladders, self.chutes_list, self.ladders_list] In OOP you rarely have to return attributes. And since step is passed in as an argument the caller already knows. So I don't think you really need to return anything here. #@timer def play_gameset(self, gamecount1): """A set of games, returning associated stats array""" return [self.play_game(i) for i in range(gamecount1)] OK, I see now, you are storing the current state values after each game. Personally I'd probably create
Re: [Tutor] Mastering the fundamentals
On 03/01/14 08:30, Christian Alexander wrote: I've just recently acquired "Learning Python", and I must state that it is a fairly thorough book. However it seems as if I am learning at a very slow pace, so my question is, as far as setting a goal to master the basics, where should I be within a years time? It depends on where you start from. Can you program in other languages? If so you should be very comfortable with Python programming in a year (probably much less). If you have never programmed before then Learning Python may not be the best tutorial since it assumes quite a lot of programming jargon etc is understood but if you persevere you should know the language well enough to write moderate sized programs (a few hundred lines say). Is that meaningful? Maybe not. To try a musical analogy, after a year you should be able to play simplified versions of popular tunes well enough that your friends recognize them and sing along. You could probably even try busking in the street for pennies. But you probably aren't going to be getting signed by Simon Cowell anytime soon. hth -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sqlite3 import problem
On Fri, Jan 3, 2014 at 10:36 AM, Alan Gauld wrote: > On 03/01/14 02:17, Matthew Ngaha wrote: >> >> im having problems importing sqlite3 on ubuntu python3. >> >>File "/usr/local/lib/python3.3/sqlite3/__init__.py", line 23, in >> >> from sqlite3.dbapi2 import * >>File "/usr/local/lib/python3.3/sqlite3/dbapi2.py", line 26, in >> from _sqlite3 import * >> ImportError: No module named '_sqlite3' > > > As a matter of interest why do you have the underscore in front of sqlite3? > Is that deliberate? > > I normally import it with just > > import sqlite3 > or > from sqlite3 import ... Hi Alan. The code in the traceback is being done internally. my code has "import sqlite3". Python finds it in this directory: /usr/local/lib/python3.3/sqlite3/ and runs the code from the traceback. I have no idea why it's using _sqlite3:( On Fri, Jan 3, 2014 at 6:12 AM, Kushal Kumaran wrote: > The /usr/local heirarchy is not used by official debian/ubuntu packages, > so other people will not have the same contents in there as you. You > must have a locally built python in /usr/local. Check the build logs if > it has complained about not being able to build the sqlite3 module. If > so, you can install all build dependencies for the offical python3 > package by running this command: > > # apt-get build-dep python3 > > And then rebuilding your local python3 installation. > On Fri, Jan 3, 2014 at 3:00 AM, Danny Yoo wrote: > This might be an Ubuntu bug or deficiency. Hi, Danny & Kushal. Originally i only had python 2.7 and 3.2 as default for Ubuntu. Kushal you're right my 3.2 has a different path to sqlite3 than /usr/local/lib/python3.3/sqlite3/ Infact i haven't been able to find its location. 3.2 imports sqlite3 with no errors. I'm currently not on ubuntu to try your instruction. Will the build logs be inside the python3.3 directory? I'm still new to linux so sorry for newbie questions. it took me a very long time to get it right when building python3.3. When you say rebuild, is there a command for doing that or do you mean simply uninstall python then build it again? On Fri, Jan 3, 2014 at 10:36 AM, Alan Gauld wrote: > On 03/01/14 02:17, Matthew Ngaha wrote: >> >> im having problems importing sqlite3 on ubuntu python3. >> >>File "/usr/local/lib/python3.3/sqlite3/__init__.py", line 23, in >> >> from sqlite3.dbapi2 import * >>File "/usr/local/lib/python3.3/sqlite3/dbapi2.py", line 26, in >> from _sqlite3 import * >> ImportError: No module named '_sqlite3' > > > As a matter of interest why do you have the underscore in front of sqlite3? > Is that deliberate? > > I normally import it with just > > import sqlite3 > or > from sqlite3 import ... > > > > -- > Alan G > Author of the Learn to Program web site > http://www.alan-g.me.uk/ > http://www.flickr.com/photos/alangauldphotos > > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sqlite3 import problem
On 03/01/2014 10:36, Alan Gauld wrote: On 03/01/14 02:17, Matthew Ngaha wrote: im having problems importing sqlite3 on ubuntu python3. File "/usr/local/lib/python3.3/sqlite3/__init__.py", line 23, in from sqlite3.dbapi2 import * File "/usr/local/lib/python3.3/sqlite3/dbapi2.py", line 26, in from _sqlite3 import * ImportError: No module named '_sqlite3' As a matter of interest why do you have the underscore in front of sqlite3? Is that deliberate? I normally import it with just import sqlite3 or from sqlite3 import ... You surprise me Alan, this is an oft used idiom in Python. A typical example would be having a fast C module but if this can't be imported fall back to a Python implementation. -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Mastering the fundamentals
Hi Christian, You can start with Google Python Class https://developers.google.com/edu/python/ Best regards, Ahmed On Jan 3, 2014 1:29 PM, "Christian Alexander" < christian.h.alexan...@gmail.com> wrote: > Hello Tutorians, > > I've just recently acquired "Learning Python", and I must state that it is > a fairly thorough book. However it seems as if I am learning at a very > slow pace, so my question is, as far as setting a goal to master the > basics, where should I be within a years time? Assuming I spend at least 2 > hours of actual coding time per day. > > > > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > > ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sqlite3 import problem
On 03/01/14 13:36, Mark Lawrence wrote: File "/usr/local/lib/python3.3/sqlite3/dbapi2.py", line 26, in from _sqlite3 import * ImportError: No module named '_sqlite3' As a matter of interest why do you have the underscore in front of sqlite3? Is that deliberate? You surprise me Alan, this is an oft used idiom in Python. A typical example would be having a fast C module but if this can't be imported fall back to a Python implementation. Yes, but that's usually hidden from the user... I didn't look closely enough at the file names in the traceback and assumed the OP was explicitly importing using the underscore. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
On 01/03/2014 12:41 PM, Alan Gauld wrote: return [step, self.move_count, self.num_chutes, self.num_ladders, self.chutes_list, self.ladders_list] In OOP you rarely have to return attributes. And since step is passed in as an argument the caller already knows [it]. So I don't think you really need to return anything here. Maybe the intent here (except from the case of step) is to conceptually isolate another part of code from the current object (here a 'game'), or from this method (play_game). So that don't they interact in a hidden way (that one cannot guess from the outside, without reading code in detail). In other words, to make code _transparent_, which is indeed a common advice (and one I approve). In this, to have the caller explicitely, obviously read information about the 'game' object, one could just: return self However, this makes no sense if the caller the cirrent method, play_game, is another method of the 'game' ;-). In this case, indeed return nothing. (All this, if I correctly understand and interpret.) Denis ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Mastering the fundamentals
On 01/03/2014 09:30 AM, Christian Alexander wrote: Hello Tutorians, I've just recently acquired "Learning Python", and I must state that it is a fairly thorough book. However it seems as if I am learning at a very slow pace, so my question is, as far as setting a goal to master the basics, where should I be within a years time? Assuming I spend at least 2 hours of actual coding time per day. I'd say there is no common pace. Differences between (future) programmers are huge. Also faster pace at a given period does not mean higher quality or competence eventually, and lower pace at a given period does not mean lower quality or competence eventually. (This applies to any complex or creative domain.) (I'd also say: do as you feel it; listen to, be confident in, follow your intuition; who alse can know what's good [pace] for you.) Denis ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] ValueError: could not convert string to float: '13,2'
On 12/31/2013 12:56 PM, Mark Lawrence wrote:
import locale
# Set to users preferred locale:
locale.setlocale(locale.LC_ALL, '')
# Or a specific locale:
locale.setlocale(locale.LC_NUMERIC, "en_DK.UTF-8")
print(locale.atof("3,14"))
This is a good solution, but be aware that it could impact other parts
of your porgram as well, particularly if this is a read in data set from
a non-local region. Also, in places where commas are used as decimal
points, it's also common to use periods as commas:
>>> print(locale.atof("123.456,14"))
123456.14
Emile
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Re: [Tutor] ValueError: could not convert string to float: '13,2'
On Fri, Jan 3, 2014 at 11:53 AM, emile wrote:
> On 12/31/2013 12:56 PM, Mark Lawrence wrote:
>>
>> import locale
>>
>> # Set to users preferred locale:
>> locale.setlocale(locale.LC_ALL, '')
>> # Or a specific locale:
>> locale.setlocale(locale.LC_NUMERIC, "en_DK.UTF-8")
>> print(locale.atof("3,14"))
>
> This is a good solution, but be aware that it could impact other parts of
> your porgram as well, particularly if this is a read in data set from a
> non-local region. Also, in places where commas are used as decimal points,
> it's also common to use periods as commas:
>
print(locale.atof("123.456,14"))
> 123456.14
If you're writing a library, don't modify the process locale. That's
for an application to set, preferably only once at startup. Use some
other library such as ICU:
>>> import icu
>>> lc = icu.Locale.createCanonical('da_DK.utf-8')
>>> lc.getDisplayLanguage()
'Danish'
>>> lc.getDisplayCountry()
'Denmark'
>>> nf = icu.NumberFormat.createInstance(lc)
>>> nf.parse('123.456,14').getDouble()
123456.14
http://userguide.icu-project.org/locale
http://userguide.icu-project.org/formatparse/numbers
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Re: [Tutor] What's in a name?
On Fri, Jan 3, 2014 at 4:50 AM, Danny Yoo wrote:
> Quick thing. Please look at the following small program:
>
> #
> d1 = {1 : 'one'}
> d2 = d1
> d2[2] = 'two'
> print(d1)
> print(d2)
> #
>
> Predict what this prints out. Write your prediction on a piece of paper.
>
> Then run the program. Does it match what you wrote?
>
> If not, start asking questions. If so, then I'm puzzled. :P
>
>
> Thanks Danny: I understand this issue when I'm looking right at it, but it
can still slip past me with a moments inattention... as soon as you pointed
it out, I bruised my forehead by slapping it so hard. Thanks.
Actually, it's funnier than that: I now notice that the code I swiped from
you passes the original arrays, not even the "copies" which aren't copies.
That's what I meant to do: make a copy when I wrote chute_nums = chutes. So
I should have passed chute_nums to summarize_game, but it still wouldn't
work (because it's not a copy). More below.
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Re: [Tutor] What's in a name?
On Fri, Jan 3, 2014 at 9:03 AM, spir wrote: > On 01/03/2014 12:41 PM, Alan Gauld wrote: > >> >> return [step, self.move_count, self.num_chutes, >>> self.num_ladders, self.chutes_list, self.ladders_list] >>> >> >> In OOP you rarely have to return attributes. And since step >> is passed in as an argument the caller already knows [it]. So I >> >> don't think you really need to return anything here. >> > Alas, it's uglier than all that, and probably inherently non-OOP organized. The calling method DOES know the step variable (attribute? it's not part of a class, is it still an attribute?), since it's using it to iterate through a list: but that variable is gone by the time the play_game returns, and yet I want to ensconce it in the data structure to keep track of the different games... And so I pass it in to save it to the data structure. It's ugly, and probably not the right way to do that (post script: I think I figured this out below). Calling method: return [self.play_game(i) for i in range(gamecount1)] def play_game(self, step): # various stuff happens, but step is just passed through to be stored in the structure that the calling method is contributing to return [step, self.move_count, self.num_chutes, self.num_ladders, self.chutes_list, self.ladders_list] > Maybe the intent here (except from the case of step) is to conceptually > isolate another part of code from the current object (here a 'game'), or > from this method (play_game). So that don't they interact in a hidden way > (that one cannot guess from the outside, without reading code in detail). > In other words, to make code _transparent_, which is indeed a common advice > (and one I approve). > > In this, to have the caller explicitely, obviously read information about > the 'game' object, one could just: > return self > > However, this makes no sense if the caller the cirrent method, play_game, > is another method of the 'game' ;-). In this case, indeed return nothing. > > (All this, if I correctly understand and interpret.) > > Denis Well, I sort of mangle OOP still. Here's the issue: I have this play_game method of Game, which returns/fills in the "results" of a game in the form of a list of ints & lists. What I though I want is to play lots of games, gather all those game "results" into a big array (just another list really, of course), and then do stats/analsis on that array. But I think my thinking is broken here: I am trying to create a list of game results, whereas I should be creating a list of games (with their corresponding attributes)... And that should happen altogether outside the Game glass. I imagine I should have another class for that, say GameArray... but that's just a first thought on the next reorganization... So I guess my Game class should have an attribute like game_number, corresponding to step variable above, and GameArray should do something like... game1 = Game() # instance of Game for i in range(gamecount): game_array[i] = game1.play_game(i) (inside play_game: self.game_number = i) And I guess GameArray can hold all the stats/analysis/printing functions, since that's the object they operate on... This sounds like the right direction here, but I don't completely trust my own thinking yet on this stuff. In retrospect, my need for a reset method probably indicated I was going the wrong direction, and probably popped up as soon as I tried to deal with a multitude of games within the Game class itself. thanks as always! ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] idle problem
Hello to everyone, Sudenly Im having troubles opening files with the idle editor. When I open a file it appears in blank, and can not close it anymore. My OS is ubuntu 13.10 (64 bits) and my python version is 2.7.5. Regards, Igor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] idle problem
On Fri, Jan 3, 2014 at 2:35 PM, I. Alejandro Fleischer wrote: > > Sudenly Im having troubles opening files with the idle editor. When I open a > file it appears in blank, and can not close it anymore. > > My OS is ubuntu 13.10 (64 bits) and my python version is 2.7.5. Maybe something is wrong with a configuration file. Try renaming the .idlerc directory: mv ~/.idlerc ~/.idlerc.bak ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
On Fri, Jan 3, 2014 at 6:41 AM, Alan Gauld wrote: > This is off topic but a couple of points about the OOP stuff... > > thanks Alan, this was helpful. > "If I'm iterating a variable through a series of list names, > for future processing, I would like to print the name of the > list the variable is set to in a given moment... " > > Remember that variables in Python are just names. > So we can rewrite your statement as > > "If I'm iterating a name through a series of list names, for future > processing, I would like to print the name of the list the name is set to > in a given moment... " > > And since the list names are just strings we can write: > > "If I'm iterating a name through a list of strings, for future processing, > I would like to print the name in a given moment... > > So the answer to your question is just to print the string. > The real challenge, as we have discovered, is how to access > the list that is named by the string. And the usual way to > map strings to objects is via a dictionary not by using eval(). > > Here's the thing: I think most of my "problems" go away with better design. But in case I'm wrong, what I was trying to do, which I would think could sometimes be helpful, is printing the name of an object along with it's output/results... I don't think there's any way to do the opposite of eval(), that is, create a string from an object name. Or am I just missing something here (I THINK the right way to do this is add, if necessary, and __name__ method, or at least a .name attribute, to the class... though now that I think about it I think that still doesn't solve the problem, it names the class not the instance. Do you really need the num_xxx variables? > Using len(xxx_list) is more reliable that depending on your > code to maintain the values. It may be that you need them > for a performance optimisation but given that games are > not normally CPU bound that seems unlikely. > > It was something between performance optimization and historical artifact. I'm pretty sure the effect of it's optimization was to slow the program down. It/they are redundant. > > return [tchutes, tladders] # only one will be != 0 >> > > I don't understand the tchutes/tladders stuff? They hold the > target position or zero (the return comment is wrong BTW since both > could be zero). Why not just have a single variable called target > or somesuch? Also if you must return two values its probably better to use > a tuple rather than a list. > > Oh god, you are airing all my dirty laundry. On each move, the position might be a chute, or a ladder, or neither. After I use that position to determine if it's a chute or ladder, it seems like it makes sense to store that info explicitly, to avoid another dictionary lookup. Probably another optimization mistake. So if the first returned list entry has a number in it, it's a chute, and add it to the list of chutes this game traversed, and same with the second entry and ladder... I suspect I should do this entirely differently. > > Shouldn't the self.position assignment be part of reset()? > > It used to be, but then I realized it's not a state I need to save: I meant to change it to a local variable. > > while self.position < 100: >> gamecandl = self.move() # [chute, ladder] or [0, 0] >> if gamecandl[0] != 0: # populate chutes list >> self.chutes_list.append(gamecandl[0]) >> if gamecandl[1] != 0: # populate ladders list >> self.ladders_list.append(gamecandl[1]) >> > > Why don't you do this update of the lists in the move() code. > It's where it logically happens and saves passing back the > list/tuple and then having to test it here. This just adds > extra work. > > Hmm. That seems like a good point. I think it all shifts when I properly implement the Game() class. Next draft. > > return [step, self.move_count, self.num_chutes, >> self.num_ladders, self.chutes_list, self.ladders_list] >> > > In OOP you rarely have to return attributes. And since step > is passed in as an argument the caller already knows. So I > don't think you really need to return anything here. Yes, reading this is what helped me see the direction of the next rewrite. Thanks. > > OK, I see now, you are storing the current state values > after each game. Personally I'd probably create another > method called (get_stats() or similar and have play() return > success/failure. > > o success or failure. You're edging me towards exception handling. Then your line above would be: > > return [self.get_stats() for i in range(gamecount) if self.play()] > > It keeps the purpose of the methods explicit. play() plays the game, > get_stats() returns the data. > > But there is another more OOP approach. > Create a game instance for each iteration. > Then collect the instances which then hold the data. > No need for all the extra arrays, return values, etc. > It's by using and passing
[Tutor] python, speed, game programming
-- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
Shoot, sorry for the empty message. Here's what I was going to say: I am gearing up for the next project (yeah, an eventual end to Chutes & Ladders!). It is a typing tutor, I am inclined to use it to learn Dvorak but I would expect it easily adapted to QWERTY or anything else. The basic idea is build a database of the key and response time of every keystroke, with simultaneous background processing going on, based on a customizable set of parameters to select the test text in more or less real time. So for example, I might wish to adjust the interval at which I revisit old material, to be sure I "get" it without becoming bored by it: we could call this the repetition interval, and it might well be a function that increases with time, though it might also be keyed to the speed of recall... all responses are to be saved long-term for subsequent analysis. My concern is with speed. This will have to keep up with (somewhat arbitrarily) fast typing, while doing background processing, with a GUI of course. This illustrates why I was concerned about the fact that my Chutes & Ladders game seems to run at the same speed on my 8 y.o. Core 2 Duo and my 2 y.o. Core I7 with 3-4x as much memory. This WILL require a faster machine and a more significant share of it's resources, if I develop it in the direction I am thinking. I hope Python is a good choice here, though I suppose some modules or classes or parts will have to be recoded into something faster... Any thoughts on this will be appreciated, including how to structure it in such a manner that it might be more portably applied to future versions in entirely different knowledge realms (music/midi input, language/vocabulary/audio output, etc). -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
Just to be clear: this is equal parts learning Python project, prototype tutorial software project, OOP practice, and the beginning of a more general inquiry into learning styles/paradigms/parameters... I'm (slowly) writing some of these ideas up in a separate doc. On Fri, Jan 3, 2014 at 4:53 PM, Keith Winston wrote: > Shoot, sorry for the empty message. Here's what I was going to say: > > I am gearing up for the next project (yeah, an eventual end to Chutes & > Ladders!). It is a typing tutor, I am inclined to use it to learn Dvorak > but I would expect it easily adapted to QWERTY or anything else. > > The basic idea is build a database of the key and response time of every > keystroke, with simultaneous background processing going on, based on a > customizable set of parameters to select the test text in more or less real > time. So for example, I might wish to adjust the interval at which I > revisit old material, to be sure I "get" it without becoming bored by it: > we could call this the repetition interval, and it might well be a function > that increases with time, though it might also be keyed to the speed of > recall... all responses are to be saved long-term for subsequent analysis. > > My concern is with speed. This will have to keep up with (somewhat > arbitrarily) fast typing, while doing background processing, with a GUI of > course. This illustrates why I was concerned about the fact that my Chutes > & Ladders game seems to run at the same speed on my 8 y.o. Core 2 Duo and > my 2 y.o. Core I7 with 3-4x as much memory. This WILL require a faster > machine and a more significant share of it's resources, if I develop it in > the direction I am thinking. > > I hope Python is a good choice here, though I suppose some modules or > classes or parts will have to be recoded into something faster... Any > thoughts on this will be appreciated, including how to structure it in such > a manner that it might be more portably applied to future versions in > entirely different knowledge realms (music/midi input, > language/vocabulary/audio output, etc). > > -- > Keith > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
On Fri, Jan 3, 2014 at 1:53 PM, Keith Winston wrote: > I am gearing up for the next project (yeah, an eventual end to Chutes & > Ladders!). It is a typing tutor, I am inclined to use it to learn Dvorak but > I would expect it easily adapted to QWERTY or anything else. > [snip] > > I hope Python is a good choice here, though I suppose some modules or > classes or parts will have to be recoded into something faster... Any > thoughts on this will be appreciated, including how to structure it in such > a manner that it might be more portably applied to future versions in > entirely different knowledge realms (music/midi input, > language/vocabulary/audio output, etc). Modern computers are just so absurdly fast that the overhead Python has compared to other languages just doesn't matter for the kind of work you are doing. If you typed at a hundred characters per second Python could still keep up, unless there's something about your problem you aren't describing. -- Devin ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] python problems on android
Hi. I wrote a few python programs and had them running on my phone up
to last september.
Haven't had time to work on them again till now.
Only now, they... don't work !
Not sure why and its very frustrating.
one of the errors is in response to an input request like this
g = input ("type h to use last settings ")
stops the program with this
File , line1, in
NameError: name 'h' is not defined
after I entered h
Will I have to abandon using SL4A and Python and switch to using
android/java ?
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Re: [Tutor] python problems on android
On Fri, 03 Jan 2014 22:18:00 +, blech...@fireflyuk.net wrote:
one of the errors is in response to an input request like this
g = input ("type h to use last settings ")
stops the program with this
File , line1, in
NameError: name 'h' is not defined
after I entered h
Looks to me like you were previously running python 3.x and somehow
have reverted to 2.x
Add two lines before the input ()
import sys
print (sys.version)
to see what you're using.
--
DaveA
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Re: [Tutor] python, speed, game programming
On 01/03/2014 10:53 PM, Keith Winston wrote: My concern is with speed. This will have to keep up with (somewhat arbitrarily) fast typing, while doing background processing, with a GUI of course. I wouldn't even bother. Try & see, you may be surprised. There are several factors at play: * The core processing in dealing with user input (read, decode, store, queue key strokes, etc) will be done by low-level (OS) routines written in C, with only thin Python wrappers (which essentially translate from/to python data types). * Similar point for GUI and/or other user interface layer (less so if you'd use a pure python GUI framework, but in general they're also just wrappers over C code). * The ratio between such low-level processing and actual processing code written and executed in python for your application logic is certainly high (as is usually the case), unless there is much realtime computation you did not speak about. Anyway, just try and see. This is similar to how & why python is reputed to be good (read: fast) at "number crunching": they are standard libs for that just link to low-level C routines which do about all computation, behind the stage, and very few application logic remains written *and actually executed* in python (search "numpy"). Denis ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
Hi Keith, On 3 January 2014 20:03, Keith Winston wrote: >> So the answer to your question is just to print the string. >> The real challenge, as we have discovered, is how to access >> the list that is named by the string. And the usual way to >> map strings to objects is via a dictionary not by using eval(). > > Here's the thing: I think most of my "problems" go away with better design. > But in case I'm wrong, what I was trying to do, which I would think could > sometimes be helpful, is printing the name of an object along with it's > output/results... I don't think there's any way to do the opposite of > eval(), that is, create a string from an object name. Or am I just missing > something here (I THINK the right way to do this is add, if necessary, and > __name__ method, or at least a .name attribute, to the class... though now > that I think about it I think that still doesn't solve the problem, it names > the class not the instance. Firstly a caveat/disclaimer/apology: I've not read every post in this thread in detail, so apologies if some of my comments miss the point or has otherwise been already made to death. Secondly, it seems to me you seem perhaps to think of an object's name as something intrinsic, e.g. an attribute that is (or should be) part of every object. Note you should view objects as not having intrinsic names unless *you* make it so via code. The names that you associate to your objects in your program however, are not part of your objects, instead they live separately in namespaces and do not form part of the objects themselves. To belabor the point: You should distinguish between a) references to your objects that are "name references" that live in a namespace somewhere (which some people call variables) and b) other anonymous references, e.g. just non-name references held by another object (for example such as that which is held by a list that contains your object), and c) a potential name attribute or property you might add to your objects to store some custom name that you'd like to give your object at runtime (and again, which is therefore quite separate from and distinct to any variable/namespace references that might also be referring to your object.). Generally, if you want an object to have a name, then make an attribute to represent the name and use that, as you've indeed alluded to above. It's not usually the right idea to try and introspect back to the (possibly many, or none) namespace references referring to your objects. Now, having said all that, and though I'm hesitant to even mention this in fear of muddying the waters and confusing matters by doing so, it is in fact possible (and with some caveats), to query for and retrieve all the name references for an object with a bit of querying of the Python runtime environment (specifically the garbage collector). Try this: --- import gc, itertools def names_of(obj): """Try to find the names associated to a given object.""" #Find dict objects from the garbase collector: refs_dicts = (ref for ref in gc.get_referrers(obj) if isinstance(ref, dict)) #Get a single chained generator for all the iteritems() iterators in all the dicts keyvalue_pairs = itertools.chain.from_iterable(refd.iteritems() for refd in refs_dicts) #Return a list of keys (names) where the value (obj) is the one we're looking for: return [k for k, v in keyvalue_pairs if v is obj] x = [] y = x z = [x] print names_of(z[0]) --- As you might expect, the last line outputs the 2 names for the list initially named "x" above, e.g. ['x', 'y'] As for generating a string representation of an object, by convention the output of the repr() function is usually supposed to give you a string _repr_esentation (geddit) that should, if submitted to the Python interpreter (or eval), give you back an equivalent object to the one that was passed to repr(). This however is not guaranteed and you should _NOT_ rely on repr()/eval() if you're trying to serialise/deserialize your objects, not least due to the security dangers implied by eval. Instead, use the pickle module: http://docs.python.org/2/library/pickle.html HTH, Walter ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
Hi, The code in my last post got line wrapped which will break if directly tried out. To avoid possible confusion I paste a version below with shorter lines which should avoid the problem: import gc, itertools def names_of(obj): """Try to find the names associated to a given object.""" #Find dict objects from the garbage collector: refs_dicts = (ref for ref in gc.get_referrers(obj) if isinstance(ref, dict)) #Get a single chained generator for all the iteritems() iterators #in all the dicts keyvalue_pairs = itertools.chain.from_iterable( refd.iteritems() for refd in refs_dicts) #Return a list of keys (names) where the value (obj) is the one #we're looking for: return [k for k, v in keyvalue_pairs if v is obj] x = [] y = x z = [x] print names_of(z[0]) ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] python problems on android
Thanks Dave. I was using 3.2.2 and uninstalled it earlier as it was giving me strange messages. Just reinstalled to remind myself what these were. here goes, WARNING: linker: libpython3.2m.so has text relocations this is wasting memory and is a security risk. Please fix the warning message repeats replacing the module name with several others like array.cpython-32m.so It ran my program with the same Name Error:name l is not defined problem as before The error I posted was using 2.6.2 So my program crashes on both 2 and 3 ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
Okay, thanks, I'll probably be proceeding over the next few weeks, as I finish up my Chutes & Ladders project... I think I have to do a bit more code/manual reading in proportion to my coding for a bit, also. Thanks for the insights. K On Fri, Jan 3, 2014 at 6:12 PM, spir wrote: > On 01/03/2014 10:53 PM, Keith Winston wrote: > >> My concern is with speed. This will have to keep up with (somewhat >> arbitrarily) fast typing, while doing background processing, with a GUI of >> course. >> > > I wouldn't even bother. Try & see, you may be surprised. There are several > factors at play: > * The core processing in dealing with user input (read, decode, store, > queue key strokes, etc) will be done by low-level (OS) routines written in > C, with only thin Python wrappers (which essentially translate from/to > python data types). > * Similar point for GUI and/or other user interface layer (less so if > you'd use a pure python GUI framework, but in general they're also just > wrappers over C code). > * The ratio between such low-level processing and actual processing code > written and executed in python for your application logic is certainly high > (as is usually the case), unless there is much realtime computation you did > not speak about. > Anyway, just try and see. > > This is similar to how & why python is reputed to be good (read: fast) at > "number crunching": they are standard libs for that just link to low-level > C routines which do about all computation, behind the stage, and very few > application logic remains written *and actually executed* in python (search > "numpy"). > > Denis > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
Thanks Walter, I think I've got the lay of the land roughly, but my grasp is still light and imperfect. I'm pretty confident I shouldn't be doing anything like what you're describing for the level of coding I'm doing, but it's interesting to see the approach. Keith On Fri, Jan 3, 2014 at 6:56 PM, Walter Prins wrote: > Hi, > > The code in my last post got line wrapped which will break if directly > tried out. To avoid possible confusion I paste a version below with > shorter lines which should avoid the problem: > > > import gc, itertools > > def names_of(obj): > """Try to find the names associated to a given object.""" > #Find dict objects from the garbage collector: > refs_dicts = (ref for ref in gc.get_referrers(obj) > if isinstance(ref, dict)) > #Get a single chained generator for all the iteritems() iterators > #in all the dicts > keyvalue_pairs = itertools.chain.from_iterable( > refd.iteritems() for refd in refs_dicts) > #Return a list of keys (names) where the value (obj) is the one > #we're looking for: > return [k for k, v in keyvalue_pairs if v is obj] > > x = [] > y = x > z = [x] > > print names_of(z[0]) > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python problems on android
On Fri, Jan 3, 2014 at 4:26 PM, wrote: > Thanks Dave. Your email doesn't appear to be in response to anything. I think your email client is broken, and you should switch to a different one. -- Devin ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] idle problem
Hello Alejandro! Try running idle via a terminal and see if it's throwing out any error information. (-d switch for dubug) I've moved on to a mix between PyCharm and Vim depending on how big of a "project" I'm working on, but I still have idle installed so I can probably help a bit more if there's more details to be had. - Kodiak On Fri, Jan 3, 2014 at 2:35 PM, I. Alejandro Fleischer < iafleisc...@gmail.com> wrote: > Hello to everyone, > > Sudenly Im having troubles opening files with the idle editor. When I open > a file it appears in blank, and can not close it anymore. > > My OS is ubuntu 13.10 (64 bits) and my python version is 2.7.5. > > Regards, > > Igor > > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > > ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] python problems on android
Hi. I wrote a few python programs and had them running on my phone up to last
september.
Haven't had time to work on them again till now.
Only now, they... don't work !
Not sure why and its very frustrating.
one of the errors is in response to an input request like this
g = input ("type h to use last settings ")
stops the program with this
File , line1, in
NameError: name 'h' is not defined
after I entered h
Will I have to abandon using SL4A and Python and switch to using android/java ?
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Re: [Tutor] python problems on android
Hi Roger, Check whether or not you are running Python 3 or Python 2. I strongly suspect you should be using 3, but have run it as a Python 2 program by accident. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] idle problem
On 03/01/14 19:35, I. Alejandro Fleischer wrote: Sudenly Im having troubles opening files with the idle editor. When I open a file it appears in blank, and can not close it anymore. How are you opening it? How do you run IDLE? How do you open a file? What does the 'blank' window display as a title? -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
On 03/01/14 21:53, Keith Winston wrote: Ladders!). It is a typing tutor, I am inclined to use it to learn Dvorak but I would expect it easily adapted to QWERTY or anything else. ... My concern is with speed. This will have to keep up with (somewhat arbitrarily) fast typing, Lets see. The speed record for touch typing is around 150 wpm with average word being about 5 chars, so a speed of about 750 cpm or 12.5cps That's about 80ms between letters. Python on a modern PC can probably execute around 100k lines of code(*) per second or 100 per millisecond. That's 8k lines executed between each keypress for the worlds fastest typist. I used to use a typing tutor that was written in old GW Basic on the original IBM PC (speed 4.7MHz) and it had no problem analyzing my stats (albeit at a modest 40-50 wpm). I'd worry about speed after you find you need to. (*)Caveat: I haven't tried any kind of objective test and of course some Python 'lines' are equal to many lines of simpler languages - think list comprehensions. But in practice I still don't think you will have a big problem. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
Just to be clear, what I'm asking this typing tutor to do is vastly more than normal, albeit still not seemingly very much. In most programs, they give you a sentence or paragraph to type, and then time how long it takes. I'm talking about timing every keypress, and modifying the text stream based on that. The thing that put me on edge was noticing that my simple Chutes & Ladders game doesn't go ANY faster on a machine that benchmarks perhaps 1000 times faster than another... Keith On Fri, Jan 3, 2014 at 8:17 PM, Alan Gauld wrote: > On 03/01/14 21:53, Keith Winston wrote: > > Ladders!). It is a typing tutor, I am inclined to use it to learn Dvorak >> but I would expect it easily adapted to QWERTY or anything else. >> ... >> >> >> My concern is with speed. This will have to keep up with (somewhat >> arbitrarily) fast typing, >> > > Lets see. The speed record for touch typing is around 150 wpm with average > word being about 5 chars, so a speed of about 750 cpm > or 12.5cps That's about 80ms between letters. > > Python on a modern PC can probably execute around 100k lines > of code(*) per second or 100 per millisecond. That's 8k lines > executed between each keypress for the worlds fastest typist. > > I used to use a typing tutor that was written in old GW Basic > on the original IBM PC (speed 4.7MHz) and it had no problem > analyzing my stats (albeit at a modest 40-50 wpm). > > I'd worry about speed after you find you need to. > > (*)Caveat: I haven't tried any kind of objective test and > of course some Python 'lines' are equal to many > lines of simpler languages - think list comprehensions. > But in practice I still don't think you will have a > big problem. > > > -- > Alan G > Author of the Learn to Program web site > http://www.alan-g.me.uk/ > http://www.flickr.com/photos/alangauldphotos > > > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
Truth in advertising: I just realized a Core I7 only benchmarks about 10x faster than a Core 2 Duo, using Passmark. Wow, something like 6 years newer and only 10 times? Anyway, I'd STILL expect to see some of that in the program performance, though maybe once I get it ironed out it will be a little sleeker... Keith On Fri, Jan 3, 2014 at 8:38 PM, Keith Winston wrote: > Just to be clear, what I'm asking this typing tutor to do is vastly more > than normal, albeit still not seemingly very much. In most programs, they > give you a sentence or paragraph to type, and then time how long it takes. > I'm talking about timing every keypress, and modifying the text stream > based on that. The thing that put me on edge was noticing that my simple > Chutes & Ladders game doesn't go ANY faster on a machine that benchmarks > perhaps 1000 times faster than another... > > Keith > > > On Fri, Jan 3, 2014 at 8:17 PM, Alan Gauld wrote: > >> On 03/01/14 21:53, Keith Winston wrote: >> >> Ladders!). It is a typing tutor, I am inclined to use it to learn Dvorak >>> but I would expect it easily adapted to QWERTY or anything else. >>> ... >>> >>> >>> My concern is with speed. This will have to keep up with (somewhat >>> arbitrarily) fast typing, >>> >> >> Lets see. The speed record for touch typing is around 150 wpm with >> average word being about 5 chars, so a speed of about 750 cpm >> or 12.5cps That's about 80ms between letters. >> >> Python on a modern PC can probably execute around 100k lines >> of code(*) per second or 100 per millisecond. That's 8k lines >> executed between each keypress for the worlds fastest typist. >> >> I used to use a typing tutor that was written in old GW Basic >> on the original IBM PC (speed 4.7MHz) and it had no problem >> analyzing my stats (albeit at a modest 40-50 wpm). >> >> I'd worry about speed after you find you need to. >> >> (*)Caveat: I haven't tried any kind of objective test and >> of course some Python 'lines' are equal to many >> lines of simpler languages - think list comprehensions. >> But in practice I still don't think you will have a >> big problem. >> >> >> -- >> Alan G >> Author of the Learn to Program web site >> http://www.alan-g.me.uk/ >> http://www.flickr.com/photos/alangauldphotos >> >> >> ___ >> Tutor maillist - Tutor@python.org >> To unsubscribe or change subscription options: >> https://mail.python.org/mailman/listinfo/tutor >> > > > > -- > Keith > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
[Tutor] simple arg problem
I'm trying to rewrite/reshuffle my Chutes & Ladders code, which I generally find more confusing than writing anew. Anyway, I've got a method that seems like it calls for one argument but... def populate(self, gamecount1): """populate candl_array with a set of games""" (method of a new class CandL_Array, which contains a list called candl_array) Every time I run it with -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] simple arg problem
gmail is driving me crazy. Anyway, every time I run it with: if __name__ == "__main__": tarray = CandL_Array tarray.populate(100) I get an error Traceback (most recent call last): File "/home/keithwins/Dropbox/Python/CandL8.py", line 127, in tarray.populate(100) TypeError: populate() missing 1 required positional argument: 'gamecount1' >>> Which seems to say it wants another argument, but I am in the habit of not counting the self argument... I thought I understood that. I'm sure it's something obvious, but I've been staring at it for hours. This is going to be embarrassing... On Fri, Jan 3, 2014 at 9:53 PM, Keith Winston wrote: > I'm trying to rewrite/reshuffle my Chutes & Ladders code, which I > generally find more confusing than writing anew. > > Anyway, I've got a method that seems like it calls for one argument but... > > def populate(self, gamecount1): > """populate candl_array with a set of games""" > > (method of a new class CandL_Array, which contains a list called > candl_array) > > Every time I run it with > > > -- > Keith > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] simple arg problem
On Fri, Jan 3, 2014 at 9:56 PM, Keith Winston wrote: > > if __name__ == "__main__": > tarray = CandL_Array > tarray.populate(100) > > I get an error > > Traceback (most recent call last): > File "/home/keithwins/Dropbox/Python/CandL8.py", line 127, in > tarray.populate(100) > TypeError: populate() missing 1 required positional argument: 'gamecount1' > > Which seems to say it wants another argument, but I am in the habit of not > counting the self argument... I thought I understood that. I'm sure it's > something obvious, but I've been staring at it for hours. This is going to > be embarrassing... You've assigned the class to `tarray` instead of assigning an instance of the class. Forgetting to call() is a common mistake. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] simple arg problem
Ah, more briefly: parens. Wow, okay then. Thanks. On Fri, Jan 3, 2014 at 10:14 PM, eryksun wrote: > On Fri, Jan 3, 2014 at 9:56 PM, Keith Winston wrote: > > > > if __name__ == "__main__": > > tarray = CandL_Array > > tarray.populate(100) > > > > I get an error > > > > Traceback (most recent call last): > > File "/home/keithwins/Dropbox/Python/CandL8.py", line 127, in > > tarray.populate(100) > > TypeError: populate() missing 1 required positional argument: > 'gamecount1' > > > > > Which seems to say it wants another argument, but I am in the habit of > not > > counting the self argument... I thought I understood that. I'm sure it's > > something obvious, but I've been staring at it for hours. This is going > to > > be embarrassing... > > You've assigned the class to `tarray` instead of assigning an instance > of the class. Forgetting to call() is a common mistake. > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
On 03/01/2014 21:41, Keith Winston wrote: -- Keith Frankly I think you're lining up to jump fences when you're actually riding on the flat :) -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] python, speed, game programming
On Fri, Jan 3, 2014 at 11:14 PM, Mark Lawrence wrote: > On 03/01/2014 21:41, Keith Winston wrote: > >> -- >> Keith >> >> > Frankly I think you're lining up to jump fences when you're actually > riding on the flat :) > Fair enough, but I am thinking of the next project as a long-term dabbling: hopefully my abilities will rise to my concept... I guess I'm about 3 weeks into Python (and OOP) so far, of course my ability to focus on it will depend on work and other pressures, but I'm amazed at how accessible this language is. Anyway, thanks to you and everyone who've helped me as I crawl on the flat... this group has been way more than invaluable. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] simple arg problem
On Fri, Jan 03, 2014 at 09:56:25PM -0500, Keith Winston wrote:
> gmail is driving me crazy. Anyway, every time I run it with:
>
> if __name__ == "__main__":
> tarray = CandL_Array
> tarray.populate(100)
>
> I get an error
>
> Traceback (most recent call last):
> File "/home/keithwins/Dropbox/Python/CandL8.py", line 127, in
> tarray.populate(100)
> TypeError: populate() missing 1 required positional argument: 'gamecount1'
> >>>
Eryksun has already solved your immediate problem, but I'd like to point
out that the above has a couple of code smells.
Are you familiar with the concept of a code smell? Code which smells
wrong might not be wrong, but it's worth giving it a good hard long look
just to be sure. Like Grandma used to say about your nappies, "If it
stinks, change it", code smells usually suggest there's a problem with
the code.
http://www.codinghorror.com/blog/2006/05/code-smells.html
Like parmesan and blue cheeses, or durian fruit, there are a few
exceptions, but normally code is like food: it only smells bad when it
has gone off. You should never write smelly code without giving it a
good, hard look.
Anyway, back to your code... you have a class CandL_Array which
apparently you call with no arguments. If it needed arguments, you
wouldn't have made the error you did, which is to forget to include
parentheses:
# No
tarray = CandL_Array # makes tarray an alias to the class
# Yes
tarray = CandL_Array() # makes tarray an instance of the class
If CandL_Array() needed arguments, you wouldn't have forgotten the round
brackets, and wouldn't have got the error you did. So there's a little
whiff of a smell right there... why does the class not take any
arguments? That suggests that every instance it creates is exactly the
same as every other instance. That's not necessarily wrong, but it is a
little bit whiffy.
But then there's the next line:
tarray.populate(100)
Apparently, and I'm reading between the lines here, once you create the
CandL_Array instance, you can't use it until you populate it. If I'm
right, that's pretty smelly. That means you have errors like this:
tarray = CandL_Array() # Initialise an instance.
tarray.play_game() # or something, you don't show that part of the code
which blows up in your face because you forgot to call populate first.
That's ugly, stinking code. Imagine if you had to write code like this:
x = float("12.345")
x.prepare() # Make the float ready to use
y = x + 1.0 # Now we can use it!
Yuck.
Most of the time, creating an instance should do everything needed to
prepare it for use. I suspect that your game is no exception. If you
need to call some method to make the instance ready to use, then the
constructor __new__ or initialiser __init__ should do so.
You don't even have to get rid of the populate method. You just need
to change this:
class CandL_Array:
def __init__(self):
...
def populate(self, size):
...
to this:
class CandL_Array:
def __init__(self, size):
...
self.populate(size)
def populate(self, size):
...
and change this:
tarray = CandL_Array()
tarray.populate(100)
to this:
tarray = CandL_Array(100)
--
Steven
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[Tutor] More or less final Chutes & Ladders
Here is what I think will be about the final version of C and L. I
rearranged it quite a bit (into 2 classes), fixed a bug or two, and
generally cleaned it up a bit. I haven't really polished it, but hopefully
it will be less difficult to read... which is to say, if anyone wants to go
through it AGAIN (at your leisure) I would appreciate comments on style,
etc.
Probably the biggest change is that I added a result() method to the
ChutesAndLadders class, that returns a list of the pertinent attributes of
each game (to be compiled into the array of games results that CandL_Array
class is all about).
Anyway, I sort of need to get off this since I need to do a lot more
reading on this language, though I may be back with early drafts of my
typing tutor before long... we'll see how that goes.
--
Keith
""" Chutes & Ladders Simulation
Simulates a number of games of Chutes & Ladders (Snakes & Ladders).
Chutes & Ladders are separate dictionaries to allow tracking of
separate stats.
Gathers the results into a list of lists of individual game results
in the form (per game) of [game_no, moves, [chutes], [ladders]]
"""
import random
from timer2 import timer
from statistics import * # from whence comes mean, variance, stdev
# Landing on a chute causes one to slide down to the corresponding value.
chutes = {16: 6, 47: 26, 49: 11, 56: 53, 62: 19, 64: 60, 87: 24, 93: 73,
95: 75, 98:78}
# Landing on a ladder (key) causes one to climb up to the corresponding
value.
ladders = {1: 38, 4: 14, 9: 31, 21: 42, 28: 84, 36: 44, 51: 67, 71: 91,
80:100}
class ChutesAndLadders:
"""Game class for Chutes & Ladders."""
def __init__(self):
self.reset()
def reset(self):
self.position = 0
self.game_number = 0
self.move_count = 0
self.chutes_list = []
self.ladders_list = []
def results(self):
return [self.game_number, self.move_count, self.chutes_list,
self.ladders_list]
#@timer
def move(self):
"""Single move, with chutes, ladders, & out of bounds.
Primary action is to move self.position, but returns a list
that consists of either the chute or ladder if landed on, if either
"""
roll = random.randint(1,6)
self.move_count += 1
self.position += roll
if self.position in chutes:
self.chutes_list.append(self.position)
self.position = chutes[self.position]
elif self.position in ladders:
self.ladders_list.append(self.position)
self.position = ladders[self.position]
elif self.position > 100: # move doesn't count, have to land
exactly
self.position -= roll
return
#@timer
def play(self, game_no):
"""Single game"""
self.reset()
self.game_number = game_no
while self.position < 100:
self.move()
return
class CandL_Array:
""" Create & analyze an array of CandL games """
candl_array = []
def __init__(self):
self.candl_array = []
#@timer
def populate(self, gamecount1):
"""populate candl_array with a set of games"""
tgame = ChutesAndLadders()
for i in range(gamecount1):
tgame.play(i)
self.candl_array.append(tgame.results())
def print_stuff(self):
self.print_gameset_stats(self.candl_array)
self.print_candl_info(self.candl_array)
def print_gameset_stats(self, garray):
print("Total number of games: ", len(garray))
print(" MovesChutesLadders")
for func in [mean, max, min, stdev]:
print("{moves:9.2f} {chutes:12.2f} {ladders:13.2f}
{fname}".format(
moves=func(tgset[1] for tgset in garray),
chutes=func(len(tgset[2]) for tgset in garray),
ladders=func(len(tgset[3]) for tgset in garray),
fname=func.__name__
))
def print_candl_info(self, garray):
""" Create two dictionaries with the same keys as chutes & ladders,
but with the total number of times each c or l is traversed (in the
entire gameset)
as the values. Then, print them. """
self.chute_nums, self.ladder_nums = dict(chutes), dict(ladders)
self.summarize_game("chutes", self.chute_nums, 2, garray)
self.summarize_game("ladders", self.ladder_nums, 3, garray)
def summarize_game(self, game_name, game_nums, game_index, garray):
tgame_nums = game_nums
for i in tgame_nums.keys(): game_nums[i] = 0
for corl in tgame_nums:
for game in garray:
tgame_nums[corl] += game[game_index].count(corl)
print("total ", game_name, "= ", sum(tgame_nums.values()))
""" def timing_report():
print("game.total, count = ", p1.game.total, p1.game.count)
print("move.total, count = ", p1.move.total, p1.move.count)
"""
def run_CandL(gamecount):
tarray = CandL_Array
Re: [Tutor] simple arg problem
Hi Steven, tarray = CandL_Array(100) Yes, that's definitely better. I'll make that change. Thanks, makes sense. I'd already posted my "finished" version, so I probably won't repost with this small change right now. Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
On Fri, Jan 03, 2014 at 12:29:34AM -0500, Keith Winston wrote:
> Hmm, maybe I stumbled upon at least one approach, turning the problem
> around. Make it something like:
>
> for i in ["alist", "blist", "clist"]
> i[3] = "okey dokey "
> print(eval(i)[3], i)
>
> Of course I've been staring at this for a while, but as soon as I post I
> find a way... this is my first use of eval()
And now that you've discovered eval(), do yourself a favour and forget
all about it.
- eval is dangerous. The number one cause of software vulnerabilities
(i.e. bugs which can be used by viruses and malware) today is code
ejection, which is a fancy way of saying "somebody screwed up with
eval or the equivalent".
- eval is slow. In Python, at least, using eval("something()") is
about ten times slower than just calling something(). That's because
the slow process of parsing and compiling the text into executable
code takes place at run-time instead of compile-time.
- eval is confusing. While it's possible to use eval in simple, easy
to understand ways, there's (usually) not much point in that. So
eval normally only gets used in ways which are tricky to write and
tricky to understand.
- There is very little that cannot be done without eval. It is rarely
the best solution, and even more rarely the only solution.
My recommendation is, any time you get the urge to use eval in code,
go take a cold shower until the urge goes away. Exceptions can be made
for experts and for interactive use at the REPL.
Your code above is probably better written something like this:
for name in ["alist", "blist", "clist"]:
thelist = vars()[name]
thelist[3] = "okey dokey "
print(name, "=", thelist)
--
Steven
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Re: [Tutor] What's in a name?
On Fri, Jan 3, 2014 at 11:59 PM, Steven D'Aprano wrote: > thelist = vars()[name] I see: vars() certainly looks less dangerous than eval(), but I'm guessing that's still smelly code? I hadn't known about vars() or I probably would have used it. -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fwd: What's in a name?
On Fri, Jan 03, 2014 at 01:55:29AM -0500, Keith Winston wrote:
[...]
> I want to iterate through a bunch of lists, subsequently printing both list
> members (via indexing, for example) and the name of the list I'm on.
Why? What does this gain you?
Now, it's true that when *debugging code*, being able to see the name of
the variable and the contents of the variable is useful. But in ordinary
code, why would you care to print the name of the variable and its
contents. Who cares what the variable is named?
Debuggers stick all sorts of nasty hooks into the running interpreter in
order to do this (and much more), and we should all be thankful that (1)
debuggers exist, (2) that they aren't running by default, and most
importantly (3) that we don't have to write code like them.
In addition to powerful debuggers, we also have fantastic poor-man's
debugger called "print":
for name, value in zip(
'alist blist clist'.split(), [alist, blist, clist]):
print(name, "=", value)
Yes, it's a little bit messy code. We have to repeat the name of the
variable twice. But this isn't code that will hang around in the
finished program. It only need exist for just long enough to debug the
problem we're having (you are having a problem, I presume?), then, it's
job done, it's gone. (Be ruthless at deleting code that isn't pulling
its weight.) And in the meantime, the rest of our code doesn't need to
use any nasty indirect code, it can just use (say) alist.append(42)
instead of eval('alist').append(42).
For longer-lasting indirect code, rather than use eval, its better to do
something like this:
namespace = {
'alist': [1, 2, 4, 8, 16, 32],
'blist': ['fe', 'fi', 'fo', 'fum'],
'clist': [1.5, 2.5, 3.5, 4.5, 5.5, 6.5]
}
for name, value in namespace.items():
print(name, "=", value)
eval is a nuclear-powered bulldozer. Don't use it for cracking nuts.
--
Steven
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[Tutor] Copying [was Re: What's in a name?]
On Fri, Jan 03, 2014 at 01:53:42PM -0500, Keith Winston wrote: > That's what I meant to do: make a copy when I wrote chute_nums = chutes. So > I should have passed chute_nums to summarize_game, but it still wouldn't > work (because it's not a copy). Python never makes a copy of objects when you pass them to a function or assign them to a name. If you want a copy, you have to copy them yourself: import copy acopy = copy.copy(something) ought to work for just about anything. (Python reserves the right to not actually make a copy in cases where it actually doesn't matter.) There are a couple of shortcuts for this: # copy a dictionary new = old.copy() # copy a list, or tuple new = old[:] # make a slice from the start to the end -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
On Sat, Jan 04, 2014 at 03:59:19PM +1100, Steven D'Aprano wrote: > - eval is dangerous. The number one cause of software vulnerabilities > (i.e. bugs which can be used by viruses and malware) today is code > ejection, which is a fancy way of saying "somebody screwed up with > eval or the equivalent". Sigh. It's spelled code *injection*. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Copying [was Re: What's in a name?]
On 04/01/2014 05:44, Steven D'Aprano wrote: On Fri, Jan 03, 2014 at 01:53:42PM -0500, Keith Winston wrote: That's what I meant to do: make a copy when I wrote chute_nums = chutes. So I should have passed chute_nums to summarize_game, but it still wouldn't work (because it's not a copy). Python never makes a copy of objects when you pass them to a function or assign them to a name. If you want a copy, you have to copy them yourself: import copy acopy = copy.copy(something) ought to work for just about anything. (Python reserves the right to not actually make a copy in cases where it actually doesn't matter.) There are a couple of shortcuts for this: # copy a dictionary new = old.copy() # copy a list, or tuple new = old[:] # make a slice from the start to the end Please be aware of the difference between deep and shallow copies see http://docs.python.org/3/library/copy.html -- My fellow Pythonistas, ask not what our language can do for you, ask what you can do for our language. Mark Lawrence ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] What's in a name?
On Sat, Jan 04, 2014 at 12:32:19AM -0500, Keith Winston wrote: > On Fri, Jan 3, 2014 at 11:59 PM, Steven D'Aprano wrote: > > > thelist = vars()[name] > > > I see: vars() certainly looks less dangerous than eval(), but I'm guessing > that's still smelly code? I hadn't known about vars() or I probably would > have used it. Yes, it's still a bit smelly: but only a bit, since while "direct" code is the idea, sometimes the only way to do things is with one (or two) layers of indirection. Code should (as a general rule) not rely on, or be affected by, the name of the variable. Functions which inspect the running environment (i.e. peek deep inside the interpreter) or use eval or other techniques to operate "behind the scenes" on *names* rather than values can often lead to confusing code. As debugging tools, they're useful. Putting such functionality inside normal everyday programs is a code smell. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Copying [was Re: What's in a name?]
Thanks for all this. I ended up using newdict = dict(olddict), which seemed to work fine. I hadn't heard about the copy module until now. I had heard about deep/shallow copies, though in this particular example (all int dicts), I don't think there's a difference...? On Sat, Jan 4, 2014 at 12:50 AM, Mark Lawrence wrote: > On 04/01/2014 05:44, Steven D'Aprano wrote: > >> On Fri, Jan 03, 2014 at 01:53:42PM -0500, Keith Winston wrote: >> >> That's what I meant to do: make a copy when I wrote chute_nums = chutes. >>> So >>> I should have passed chute_nums to summarize_game, but it still wouldn't >>> work (because it's not a copy). >>> >> >> Python never makes a copy of objects when you pass them to a function or >> assign them to a name. If you want a copy, you have to copy them >> yourself: >> >> import copy >> >> acopy = copy.copy(something) >> >> >> ought to work for just about anything. (Python reserves the right to not >> actually make a copy in cases where it actually doesn't matter.) >> >> There are a couple of shortcuts for this: >> >> # copy a dictionary >> new = old.copy() >> >> # copy a list, or tuple >> new = old[:] # make a slice from the start to the end >> >> >> > Please be aware of the difference between deep and shallow copies see > http://docs.python.org/3/library/copy.html > > -- > My fellow Pythonistas, ask not what our language can do for you, ask what > you can do for our language. > > Mark Lawrence > > > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > -- Keith ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
