Re: Pylint prefers list comprehension over filter...

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From	Stephen Hansen <me@ixokai.io>
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Subject	Re: Pylint prefers list comprehension over filter...
Date	Thu, 05 May 2016 18:37:11 -0700
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On Thu, May 5, 2016, at 06:26 PM, Christopher Reimer wrote:
> Which is one is correct (Pythonic)? Or does it matter?

First, pylint is somewhat opinionated, and its default options shouldn't
be taken as gospel. There's no correct: filter is fine.

That said, the general consensus is, I believe, that list comprehensions
are good, and using them is great.

In your case, though, I would not use a list comprehension. I'd use a
generator comprehension. It looks almost identical:

    ''.join(x for x in string if x.isupper())

The difference is, both filter and your list comprehension *build a
list* which is not needed, and wasteful. The above skips building a
list, instead returning a generator, and join pulls items out of it one
at a time as it uses them. No needlessly creating a list only to use it
and discard it.

-- 
Stephen Hansen
  m e @ i x o k a i  . i o

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Thread

Re: Pylint prefers list comprehension over filter... Stephen Hansen <me@ixokai.io> - 2016-05-05 18:37 -0700
  Re: Pylint prefers list comprehension over filter... Dan Sommers <dan@tombstonezero.net> - 2016-05-06 02:46 +0000
    Re: Pylint prefers list comprehension over filter... Chris Angelico <rosuav@gmail.com> - 2016-05-06 12:55 +1000
    Re: Pylint prefers list comprehension over filter... Stephen Hansen <me+python@ixokai.io> - 2016-05-05 19:57 -0700
      Re: Pylint prefers list comprehension over filter... Steven D'Aprano <steve@pearwood.info> - 2016-05-06 22:42 +1000
    Re: Pylint prefers list comprehension over filter... Dan Sommers <dan@tombstonezero.net> - 2016-05-06 03:07 +0000
      Re: Pylint prefers list comprehension over filter... Chris Angelico <rosuav@gmail.com> - 2016-05-06 13:18 +1000
    Re: Pylint prefers list comprehension over filter... Christopher Reimer <christopher_reimer@icloud.com> - 2016-05-07 12:37 -0700

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