Re: [Tutor] Removing lines in string-table
My code: > > for line in fileNames: > > if line[-10:] == '_thumb.jpg': > > fileNames.remove(line) Chris wrote: > The above will not work if two successive lines contain the target > text. When you remove the one, its neighbor "slides over" to take the > place of the one removed and then when you proceed to the "next" line > you are actually skipping the one that slid over. Oh, yeah, that's right. I just didn't notice it... Thanks for correcting me! Actually it wouldn't have mattered (I think) because the list contains x.jpg and x_thumb.jpg which have been collected by os.listdir(). At least I suppose that it would be like [x.jpg, x_thumb.jpg, y.jpg, y_thumb.jpg] or am I completely wrong? But thanks for good suggestions, I replaced my code with the list comprehension method and it works now. Thanks! Yours, -- Olli Rajala <>< Tampere, Finland http://www.students.tut.fi/~rajala37/ "In theory, Theory and Practice should be the same. But in practice, they aren't." - Murphy's Proverbs ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Removing lines in string-table
On Tuesday, May 17, 2005, at 08:35 America/Chicago,
[EMAIL PROTECTED] wrote:
> I have a string table (don't recall the right word used in Python
> right now) and would like to remove every 'cell' that contains a
> string '_thumb.jpg'. There are 1-> digits before the string if that
> matters. I made a for-loop that does what I want to:
>
> for line in fileNames:
> if line[-10:] == '_thumb.jpg':
> fileNames.remove(line)
>
> But I really doubt that it's not the best way to do this. So, any
> comments are really appreciated.
>
The above will not work if two successive lines contain the target
text. When you remove the one, its neighbor "slides over" to take the
place of the one removed and then when you proceed to the "next" line
you are actually skipping the one that slid over. This could be
remedied with using indices to access the list, but perhaps a better
approach is to use filter or a list comprehension to remove the target
lines:
###
def myfilter(x):
return not x.endswith('_thumb.jpg')
fileNames =filter(myfilter, fileNames)
# OR
fileNames =[x for x in fileNames if not x.endswith('_thumb.jpg')]
###
/c
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Re: [Tutor] Removing lines in string-table
> Looks like a job for a list comprehension:
>
> fileNames = [element for element in fileNames if not element.endswith
> ("_thumb.jpg")]
Thanks Max! It seem to work, but now I have to do some reading,
because I have no idea why it works or what it really does. :) But
thanks anyway.
Yours,
--
Olli Rajala <><
Tampere, Finland
http://www.students.tut.fi/~rajala37/
"In theory, Theory and Practice should be
the same. But in practice, they aren't."
- Murphy's Proverbs
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Re: [Tutor] Removing lines in string-table
On May 17, 2005, at 08:52, Olli Rajala wrote:
> Okay,
> I have a string table (don't recall the right word used in Python
> right now)
It's called a list, or an array.
> and would like to remove every 'cell' that contains a
> string '_thumb.jpg'. There are 1-> digits before the string if that
> matters. I made a for-loop that does what I want to:
>
> for line in fileNames:
> if line[-10:] == '_thumb.jpg':
> fileNames.remove(line)
>
> But I really doubt that it's not the best way to do this. So, any
> comments are really appreciated.
Looks like a job for a list comprehension:
fileNames = [element for element in fileNames if not element.endswith
("_thumb.jpg")]
-- Max
maxnoel_fr at yahoo dot fr -- ICQ #85274019
"Look at you hacker... A pathetic creature of meat and bone, panting
and sweating as you run through my corridors... How can you challenge
a perfect, immortal machine?"
___
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[Tutor] Removing lines in string-table
Okay, I have a string table (don't recall the right word used in Python right now) and would like to remove every 'cell' that contains a string '_thumb.jpg'. There are 1-> digits before the string if that matters. I made a for-loop that does what I want to: for line in fileNames: if line[-10:] == '_thumb.jpg': fileNames.remove(line) But I really doubt that it's not the best way to do this. So, any comments are really appreciated. Back to coding... -- Olli Rajala <>< Tampere, Finland http://www.students.tut.fi/~rajala37/ "In theory, Theory and Practice should be the same. But in practice, they aren't." - Murphy's Proverbs ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
