[Tutor] more scraping and saving
Hi - I was helped the other day in an attempt to scrape and save a simple
web page. I'm using what I learned and trying another. It should be very
simple, but I only get the first row of names saved.
Can anybody help with an explanation?
(It's a public list of names of doctors with knows connections to the
farmaceutical industry).
This time I try to start at the right table (the third on the page) by using
the class attribute. Does that make sense?
Thanks in advance - here is the code:
import urllib2
from BeautifulSoup import BeautifulSoup
import codecs
f = codecs.open("laeger.txt", "w", encoding="Latin-1")
soup =
BeautifulSoup(urllib2.urlopen('http://www.laegemiddelstyrelsen.dk/include/88
06/tilladelse_laeger.asp').read())
for row in soup('table', {'class' : 'tableLeftRight3030'}):
tds = row('td')
output = ";".join(tds[i].string for i in (0, 1, 2, 3, 4))
f.write(output + '\n')
f.close()
Tommy Kaas
Kaas & Mulvad
Lykkesholms Alle 2A, 3.
1902 Frederiksberg C
Mobil: 27268818
Mail: tommy.k...@kaasogmulvad.dk
Web: www.kaasogmulvad.dk
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[Tutor] How does it work?
Hi All, Could you explain me how does it work, pls? == >>>r = '' >>>for c in 'abcd': r = c + r ... ... >>>r 'dcba' == Best Regards, Neo Vector ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How does it work?
On Mon, Jan 03, 2011 at 10:52:26PM +0800, Neo Vector wrote: > Hi All, Hello, > Could you explain me how does it work, pls? Sure, I'm not telling you how that works. However, I'll alter your code snippet a little bit and see if you can understand after that. > == > >>>r = '1' > >>>for c in 'abcd': print r > r = c + r > ... > ... 1 a1 ba1 cba1 > >>>r > 'dcba1' > == Let me know if you still face problems. HTH, Shrivats ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How does it work?
On Mon, Jan 03, 2011 at 08:32:18PM +0530, Shrivats wrote: > On Mon, Jan 03, 2011 at 10:52:26PM +0800, Neo Vector wrote: > > Hi All, > Hello, > > Could you explain me how does it work, pls? > > Sure, I'm not telling you how that works. However, I'll alter your code > snippet > a little bit and see if you can understand after that. > > == > > >>>r = '1' > > >>>for c in 'abcd': > print r > > r = c + r > > ... > > ... > 1 > a1 > ba1 > cba1 > > >>>r > > 'dcba1' > > == > > Let me know if you still face problems. Oh, and for more information - http://docs.python.org/tutorial/introduction.html#strings http://docs.python.org/tutorial/controlflow.html#for-statements Specifically, the idea behind this is, Strings are basically a list of characters. So they can be treated as iterable collections. :) > > HTH, > > Shrivats ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How does it work?
"Neo Vector" wrote Could you explain me how does it work, pls? == r = '' r is an empty string for c in 'abcd': c takes the value of each letter in turn r = c + r strings can be added such that the result is the concatenation of the two strings. So in this case: r becomes the sum of its old value and the current value of c repeat for the next value of c. If that doesn't help then tell us which bit(s) of it you don't understand. HTH, -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] How does it work?
- Original Message - From: "Patty" To: "Alan Gauld" Sent: Monday, January 03, 2011 9:05 AM Subject: Re: [Tutor] How does it work? Hi Folks - I read this code and tried to parse it as a pop quiz for myself ;) and have a question, maybe 2 clarifications, below: - Original Message - From: "Alan Gauld" To: Sent: Monday, January 03, 2011 8:09 AM Subject: Re: [Tutor] How does it work? "Neo Vector" wrote Could you explain me how does it work, pls? == r = '' r is an empty string for c in 'abcd': c takes the value of each letter in turn r = c + r When I first looked at this - I thought that the variable 'c' would have had to be initialized first earlier in the program. And I thought that the programmer would input a single char or a single space. I wasn't thinking counting variable for some reason. So is 'for c in', one or more of key words that Python understands that a loop is here and to actually trigger counting in a loop? Does it start with a 1 or 0 internally to do this? I also realized a mistake I may have made - maybe I confused 'for c in' with 'while c in'. r='' c="d" while c in 'abcd': r=c+r Or r='' c="d" while c in ['a', 'b', 'c', 'd']: r=c+r Also for myself I think I would have used different descriptive names for variables so that would have been less likely to throw myself off. And also doing this fast to see if I have learned. I really feel comfortable with Python now after six months and my small application is completed and looks really good. I don't know how I would have been able to make the simplest, smallest GUI part of my application - using Tkinter and PIL- fast without the references and explanations of Wayne Werner and Alan - Thanks to those on the list who are so helpful! Patty strings can be added such that the result is the concatenation of the two strings. So in this case: r becomes the sum of its old value and the current value of c repeat for the next value of c. If that doesn't help then tell us which bit(s) of it you don't understand. HTH, -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How does it work?
On 01/-10/-28163 02:59 PM, Patty wrote: for c in 'abcd': .. When I first looked at this - I thought that the variable 'c' would have had to be initialized first earlier in the program. And I thought that the programmer would input a single char or a single space. I wasn't thinking counting variable for some reason. So is 'for c in', one or more of key words that Python understands that a loop is here and to actually trigger counting in a loop? Does it start with a 1 or 0 internally to do this? There's not necessarily any integer indexing going on. for xxx in yyy is a specific syntax that specifies a loop based on a sequence. In this case the string 'abcd' is a sequence of chars, so you get c to have a value of 'a', 'b', 'c', and 'd'. But other sequences might not have any index meaning at all, so it doesn't make sense to ask if it's 0 or 1 based. For example, you can iterate over the keys of a map, where the order is irrelevant. All you really know is you'll get them all if you finish the loop. I also realized a mistake I may have made - maybe I confused 'for c in' with 'while c in'. r='' c="d" while c in 'abcd': r=c+r You messed up the indentation. But if the r=c+r line is indented, then this is an infinite loop. It'll quit when memory is exhausted. Why? Because nothing in the loop changes c. So since it's in the sequence at the beginning, it will always be. Or r='' c="d" while c in ['a', 'b', 'c', 'd']: r=c+r Similarly here. Also for myself I think I would have used different descriptive names for variables so that would have been less likely to throw myself off. Good idea. And also doing this fast to see if I have learned. I really feel comfortable with Python now after six months and my small application is completed and looks really good. I don't know how I would have been able to make the simplest, smallest GUI part of my application - using Tkinter and PIL- fast without the references and explanations of Wayne Werner and Alan - Thanks to those on the list who are so helpful! Patty HTH DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How does it work?
"Patty" wrote for c in 'abcd': c takes the value of each letter in turn When I first looked at this - I thought that the variable 'c' would have had to be initialized first earlier in the program. It is initialized earluier - in the for statement, each time through the loop it gets reinitialized to a new value. ... I wasn't thinking counting variable for some reason. So is 'for c in', one or more of key words that Python understands that a loop is here and to actually trigger counting in a loop? Does it start with a 1 or 0 internally to do this? In the case of a for loop it doesn't count as such. It takes each value from a sequience and applies it to the loop variable. Personally I think it wouyld have read better if they called it "foreach" so your loop would look like foreach char in 'abcd': or foreach item in [1,2,3,4]: etc... But they didn't so we are stuck with for. I also realized a mistake I may have made - maybe I confused 'for c in' while c in 'abcd': This is completely different. In this case we can clarify it by adding some parentheses: while (c in 'abcd'): the test is all of the bit in parens. And the test is a test of whether c is in the string or not. Python does not modify the variable 'c' in this case, that only happens with a for loop. You can read more about the various python loop structures in the loops topic of my tutorial. -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How does it work?
Yes, I knew there was something I wasn't getting. This is the explanation I was looking for - and I'm sorry about the incorrect indentation. And I agree with Alan that 'foreach' would have been a good name for this type of loop. I need to sort out 'loop structures' in my notes and read up on these for sure. Thanks, Patty - Original Message - From: "Dave Angel" To: "Patty" Cc: Sent: Monday, January 03, 2011 9:52 AM Subject: Re: [Tutor] How does it work? On 01/-10/-28163 02:59 PM, Patty wrote: for c in 'abcd': .. When I first looked at this - I thought that the variable 'c' would have had to be initialized first earlier in the program. And I thought that the programmer would input a single char or a single space. I wasn't thinking counting variable for some reason. So is 'for c in', one or more of key words that Python understands that a loop is here and to actually trigger counting in a loop? Does it start with a 1 or 0 internally to do this? There's not necessarily any integer indexing going on. for xxx in yyy is a specific syntax that specifies a loop based on a sequence. In this case the string 'abcd' is a sequence of chars, so you get c to have a value of 'a', 'b', 'c', and 'd'. But other sequences might not have any index meaning at all, so it doesn't make sense to ask if it's 0 or 1 based. For example, you can iterate over the keys of a map, where the order is irrelevant. All you really know is you'll get them all if you finish the loop. I also realized a mistake I may have made - maybe I confused 'for c in' with 'while c in'. r='' c="d" while c in 'abcd': r=c+r You messed up the indentation. But if the r=c+r line is indented, then this is an infinite loop. It'll quit when memory is exhausted. Why? Because nothing in the loop changes c. So since it's in the sequence at the beginning, it will always be. Or r='' c="d" while c in ['a', 'b', 'c', 'd']: r=c+r Similarly here. Also for myself I think I would have used different descriptive names for variables so that would have been less likely to throw myself off. Good idea. And also doing this fast to see if I have learned. I really feel comfortable with Python now after six months and my small application is completed and looks really good. I don't know how I would have been able to make the simplest, smallest GUI part of my application - using Tkinter and PIL- fast without the references and explanations of Wayne Werner and Alan - Thanks to those on the list who are so helpful! Patty HTH DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] matplotlib.pylab.plotfile formatting help
I've got a csv file that contains two data fields, the short name of a
month and an integer. I'm experimenting with pylab and ipython to get
a feel for how pylab works. I'm able to generate a bar graph from my
data, but there are two problems with it:
1. I don't want "2011" appended to the month names. This data is
from 2010, and I only want the short month name under each bar.
2. The bars are very narrow and I'm not sure how to widen them.
Here's my CSV data, stored in a file called csvdata.csv:
month,systems
Jan,17
Feb,49
Mar,77
Apr,59
May,42
Jun,137
Jul,102
Aug,115
Sep,57
Oct,134
Nov,131
Dec,197
And here's the "ipython -pylab" command that I'm using to generate the graph:
plotfile('csvdata.csv', ('month', 'systems'), plotfuncs={'systems': 'bar'},)
I've read through some of the documentation for matplotlib, but having
never used matlab or pylab before today it's a bit confusing. Does
anyone know how to solve #1 and #2 above?
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[Tutor] Initialize values from a text input file
I'm just have a little fun here, but I bet that comments will help
further elighten me on the subtleties of python.
consider the following console session:
>>> L = ['foo','bar']
>>> locals()[L[0]] = L[1]
>>> foo
'bar'
>>> 'foobar' in locals()
False
>>> 'foo' in locals()
True
>>> locals()
{'__builtins__': , 'L': ['foo',
'bar'], '__package__': None, '__name__': '__main__', 'foo': 'bar',
'__doc__': None}
Given that I have a text file as input with names and values
with a seperator (TAB, for instance)
I could initialize variables in a local scope, or I could build a
dictionary. Actually the dictionary is preferable for the targeted
application.
However, for the sake of edification, I would welcome comments on
the session above, and let's pretend that `L' is the result of a
line read from a file and split on '\t'.
TIA
tim
--
Tim
tim at johnsons-web.com or akwebsoft.com
http://www.akwebsoft.com
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Re: [Tutor] Initialize values from a text input file
"Tim Johnson" wrote
consider the following console session:
L = ['foo','bar']
locals()[L[0]] = L[1]
foo
'bar'
locals()
{'__builtins__': , 'L': ['foo',
'bar'], '__package__': None, '__name__': '__main__', 'foo': 'bar',
'__doc__': None}
I could initialize variables in a local scope, or I could build a
dictionary. Actually the dictionary is preferable for the targeted
application.
Except in extreme cases I'd say a dictionary was better in
almost any situation. Messing with locals() is a dodgy business
at best, and can lead to debugging insanity at worst, its better
to keep externally initialized data explicit in almost every case.
However, for the sake of edification, I would welcome comments on
the session above, and let's pretend that `L' is the result of a
line read from a file and split on '\t'.
My only comment: Don't go there... creating random variables
in your namespace that don't actually appear in your code makes
using global variables seem positively benign.
Once you create them what are you going to do?
Litter your code with
try:
doSomething(withNameThatMightExist)
except NameError:
doSomethingElse()
It is a minefield just waiting to suck you in.
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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Re: [Tutor] Initialize values from a text input file
Tim Johnson wrote:
I'm just have a little fun here, but I bet that comments will help
further elighten me on the subtleties of python.
consider the following console session:
L = ['foo','bar']
locals()[L[0]] = L[1]
This will not do what you think it does. In general, local variables are
not writable except the normal way by `name = value` assignment. Try
this function:
def spam():
x = 1
print(x)
locals()['x'] = 2
print(x)
The fact that assignment to locals() works in the top-level global scope
is an accident of implementation.
foo
'bar'
'foobar' in locals()
False
'foo' in locals()
True
locals()
{'__builtins__': , 'L': ['foo',
'bar'], '__package__': None, '__name__': '__main__', 'foo': 'bar',
'__doc__': None}
Given that I have a text file as input with names and values
with a seperator (TAB, for instance)
I could initialize variables in a local scope, or I could build a
dictionary. Actually the dictionary is preferable for the targeted
application.
Have you considered using the ConfigParser module?
However, for the sake of edification, I would welcome comments on
the session above, and let's pretend that `L' is the result of a
line read from a file and split on '\t'.
(1) This won't work except in the global scope.
(2) Even if it did work, do you trust the source of the text? Taking
external data provided by arbitrary untrusted users and turning it into
variables is a good way to have your computer owned by bad guys. This
technique would make your software vulnerable to code injection attacks.
You *might* be safe, if you never eval() or exec() the strings coming
out of the file. But I wouldn't bet the security of my application on
that -- especially if it were running in a web browser or on a server.
Actually, no, that's wrong -- even if you never use eval() or exec(),
you're still vulnerable to Denial Of Service attacks if the attacker can
put junk you don't expect into the file. Something as trivial as:
number = abc
in the input file could crash your application, if you aren't performing
sufficient data validation when you use "number". Or they can shadow
builtins and stop your code from working:
len = 123
# later...
len(some_list) # this will fail
This isn't a theoretical threat, something like 3 or 4 out of 5 security
vulnerabilities these days are code injection attacks, and there are a
LOT of security vulnerabilities. (The majority of these are SQL injections.)
At the very least, you should pass the items through a white list of
allowed variable names, and validate the values. Do not use a black list
of forbidden variables! The problem with the black list idea is that it
assumes that you can think of every possible vulnerability ahead of
time. You can't.
--
Steven
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Re: [Tutor] Initialize values from a text input file
* Steven D'Aprano [110103 15:03]: > Tim Johnson wrote: >> I'm just have a little fun here, but I bet that comments will help >> further elighten me on the subtleties of python. >> >> consider the following console session: > L = ['foo','bar'] > locals()[L[0]] = L[1] > > This will not do what you think it does. In general, local variables are > not writable except the normal way by `name = value` assignment. Try > this function: > > def spam(): > x = 1 > print(x) > locals()['x'] = 2 > print(x) > > > The fact that assignment to locals() works in the top-level global scope > is an accident of implementation. :) thanks for doing my homework for me. > > Have you considered using the ConfigParser module? Good tip. I will look at it > (1) This won't work except in the global scope. > > (2) Even if it did work, do you trust the source of the text? Taking > external data provided by arbitrary untrusted users and turning it into > variables is a good way to have your computer owned by bad guys. Say what? I'm not talking about anything accessible by "arbitrary users". Sorry if I gave that impression! Thanks -- Tim tim at johnsons-web.com or akwebsoft.com http://www.akwebsoft.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Initialize values from a text input file
* Alan Gauld [110103 14:47]:
>
> "Tim Johnson" wrote
>
>> consider the following console session:
> L = ['foo','bar']
> locals()[L[0]] = L[1]
> foo
>> 'bar'
> locals()
>> {'__builtins__': , 'L': ['foo',
>> 'bar'], '__package__': None, '__name__': '__main__', 'foo': 'bar',
>> '__doc__': None}
>>
>> I could initialize variables in a local scope, or I could build a
>> dictionary. Actually the dictionary is preferable for the targeted
>> application.
Actually, the dictionary is the target medium
> Except in extreme cases I'd say a dictionary was better in almost any
> situation. Messing with locals() is a dodgy business at best, and can
> lead to debugging insanity at worst, its better to keep externally
> initialized data explicit in almost every case.
I agree, that's why I said I "was having a little fun".
Now, Alan, do you know anything about PHP? If you do, can you
comment on the PHP extract() function?
thanks
--
Tim
tim at johnsons-web.com or akwebsoft.com
http://www.akwebsoft.com
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[Tutor] subclass not inheriting attributes?
Hi all, I have a solitaire game in which I use a "Pile" class. This class is meant to hold a bunch of cards, so I subclass it for the deck, the ace stacks, and the seven main stacks, defining rules and methods for each but also relying on the parent Pile class's methods and attributes. However, I keep getting an error that an attribute in the parent does not exist in the child. Below is a simplified example, but it gives me the exact same error: child object has no attribute l. class parent(object): def __init__(self, l=None): if l is None: l=[] class child(parent): def __init__(self, *args, **kwords): super(parent, self).__init__(*args, **kwords) self.l.append(5) c=child() print c.l Again, I get an error saying that 'child' object has no attribute 'l'. Python 2.7 on win7x64. Thanks. -- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Initialize values from a text input file
"Tim Johnson" wrote Now, Alan, do you know anything about PHP? If you do, can you comment on the PHP extract() function? I know enough basic PHP to read a page with code in it and get the general drift. I've never written a line of it and have learned enough about it that I don't want to! :-) Now as for extract() - it doesn't appear in my Teach Yourself PHP book, so nope, I've no idea what it does, I'd need to look it up. And I'm way too lazy, and it's way too late to do that! :-) Alan G. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
"Alex Hall" wrote class parent(object): def __init__(self, l=None): if l is None: l=[] l is a local variable inside init(). You wanted self.l... HTH, -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
On 4 January 2011 00:47, Alex Hall wrote: > class parent(object): > def __init__(self, l=None): > if l is None: l=[] > Missing "self". Perhaps you meant: class parent(object): def __init__(self, l=None): if l is None: self.l=[] else: self.l=l Walter ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
On Mon, Jan 3, 2011 at 6:47 PM, Alex Hall wrote: > Hi all, > I have a solitaire game in which I use a "Pile" class. This class is > meant to hold a bunch of cards, so I subclass it for the deck, the ace > stacks, and the seven main stacks, defining rules and methods for each > but also relying on the parent Pile class's methods and attributes. > However, I keep getting an error that an attribute in the parent does > not exist in the child. Below is a simplified example, but it gives me > the exact same error: child object has no attribute l. > > class parent(object): > def __init__(self, l=None): > if l is None: l=[] > > class child(parent): > def __init__(self, *args, **kwords): > super(parent, self).__init__(*args, **kwords) > self.l.append(5) > > c=child() > print c.l > > Again, I get an error saying that 'child' object has no attribute 'l'. > Python 2.7 on win7x64. Thanks. Try p = parent() p.l Does that do what you expected? HTH, Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
On Mon, Jan 3, 2011 at 7:47 PM, Alex Hall wrote: > Hi all, > I have a solitaire game in which I use a "Pile" class. This class is > meant to hold a bunch of cards, so I subclass it for the deck, the ace > stacks, and the seven main stacks, defining rules and methods for each > but also relying on the parent Pile class's methods and attributes. > However, I keep getting an error that an attribute in the parent does > not exist in the child. Below is a simplified example, but it gives me > the exact same error: child object has no attribute l. > > class parent(object): > def __init__(self, l=None): > if l is None: l=[] > > class child(parent): > def __init__(self, *args, **kwords): > super(parent, self).__init__(*args, **kwords) > I believe you need to pass the object both to super() and to the method itself, as in: super(parent, self).__init__(self, *args, **kwords) See the example at http://docs.python.org/library/functions.html?highlight=super#super HTH, Vern > self.l.append(5) > > c=child() > print c.l > > Again, I get an error saying that 'child' object has no attribute 'l'. > Python 2.7 on win7x64. Thanks. > > -- > Have a great day, > Alex (msg sent from GMail website) > mehg...@gmail.com; http://www.facebook.com/mehgcap > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > http://mail.python.org/mailman/listinfo/tutor > -- Vern Ceder vce...@gmail.com, vce...@dogsinmotion.com The Quick Python Book, 2nd Ed - http://bit.ly/bRsWDW ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
On 1/3/11, Wayne Werner wrote: > On Mon, Jan 3, 2011 at 6:47 PM, Alex Hall wrote: > >> Hi all, >> I have a solitaire game in which I use a "Pile" class. This class is >> meant to hold a bunch of cards, so I subclass it for the deck, the ace >> stacks, and the seven main stacks, defining rules and methods for each >> but also relying on the parent Pile class's methods and attributes. >> However, I keep getting an error that an attribute in the parent does >> not exist in the child. Below is a simplified example, but it gives me >> the exact same error: child object has no attribute l. >> >> class parent(object): >> def __init__(self, l=None): >> if l is None: l=[] Walter was right, and I changed it to if l is None: self.l=[] else: self.l=l It did not get rid of the error, though. >> >> class child(parent): >> def __init__(self, *args, **kwords): >> super(parent, self).__init__(*args, **kwords) >> self.l.append(5) >> >> c=child() >> print c.l >> >> Again, I get an error saying that 'child' object has no attribute 'l'. >> Python 2.7 on win7x64. Thanks. > > > Try > > p = parent() > p.l > > Does that do what you expected? Yes, I get [], just as I should. So the question is: if the parent class is working, why would a class that inherits it not have the l attribute? > > HTH, > Wayne > -- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
Sorry, my last post was too hasty. You also had a problem calling super. It should be like this: class parent(object): def __init__(self, l=None): if l is None: self.l=[] else: self.l=l class child(parent): def __init__(self, *args, **kwords): super(child, self).__init__(*args, **kwords) self.l.append(5) c=child() print c.l Basically: In Python 2.x "super()" doesn't know what the current class is. You have to tell it, as the first parameter. If you tell it a lie, strange things will happen. That's basically what you did. You called super(parent,...) instead of super(child,...) Have a good 2011... ;) Walter ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
On 1/3/11, Walter Prins wrote: > Sorry, my last post was too hasty. You also had a problem calling super. > It should be like this: > > class parent(object): > def __init__(self, l=None): >if l is None: self.l=[] >else: self.l=l > > class child(parent): > def __init__(self, *args, **kwords): >super(child, self).__init__(*args, **kwords) >self.l.append(5) > > c=child() > print c.l > > Basically: In Python 2.x "super()" doesn't know what the current class is. > You have to tell it, as the first parameter. If you tell it a lie, strange > things will happen. That's basically what you did. You called > super(parent,...) instead of super(child,...) I see, and this does indeed now work! Thanks! > > Have a good 2011... ;) > > Walter > -- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Initialize values from a text input file
On Tue, Jan 4, 2011 at 2:06 AM, Alan Gauld wrote: > > "Tim Johnson" wrote > >> Now, Alan, do you know anything about PHP? If you do, can you >> comment on the PHP extract() function? > > I know enough basic PHP to read a page with code in it and get the general > drift. I've never written a line of it and have learned enough about it that > I don't want to! :-) > > Now as for extract() - it doesn't appear in my Teach Yourself PHP book, so > nope, I've no idea what it does, I'd need to look it up. > And I'm way too lazy, and it's way too late to do that! :-) > extract takes an array and merges it with the local symbol table. Essentially the same thing locals() would do if it was actually writable everywhere (as Steven points out it isn't). If you ask me, this is an insanely bad idea and I have not a clue as to why you'd actually want to do this, rather than just work with the array. Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] subclass not inheriting attributes?
On 4 January 2011 01:16, Vern Ceder wrote: > I believe you need to pass the object both to super() and to the method > itself, as in: > > super(parent, self).__init__(self, *args, **kwords) > > See the example at > http://docs.python.org/library/functions.html?highlight=super#super > > HTH, > > Vern > > I've already pointed out that you're supposed to tell super() the *current* class and Alex has already indicated that it now works for him? Is there a problem with everyone on the mailing list receving posts timeously? Walter ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Initialize values from a text input file
* Hugo Arts [110103 17:12]: > On Tue, Jan 4, 2011 at 2:06 AM, Alan Gauld wrote: > > > > "Tim Johnson" wrote > > > >> Now, Alan, do you know anything about PHP? If you do, can you > >> comment on the PHP extract() function? > > > > I know enough basic PHP to read a page with code in it and get the general > > drift. I've never written a line of it and have learned enough about it that > > I don't want to! :-) > > > > Now as for extract() - it doesn't appear in my Teach Yourself PHP book, so > > nope, I've no idea what it does, I'd need to look it up. > > And I'm way too lazy, and it's way too late to do that! :-) > > > > extract takes an array and merges it with the local symbol table. > Essentially the same thing locals() would do if it was actually > writable everywhere (as Steven points out it isn't). > > If you ask me, this is an insanely bad idea and I have not a clue as > to why you'd actually want to do this, rather than just work with the > array. I've decided that members of my company (and I punished myself by appointing myself) had to learn a little PHP. At least enough to persuade a potential client why python would be a better choice. I would consider extract() one of those potent arguments as to why to use python thanks -- Tim tim at johnsons-web.com or akwebsoft.com http://www.akwebsoft.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
