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Re: Pylint prefers list comprehension over filter...

From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Subject Re: Pylint prefers list comprehension over filter...
Date 2016-05-06 13:18 +1000
Message-ID <mailman.427.1462504727.32212.python-list@python.org> (permalink)
References (1 earlier) <1462498631.232041.599637409.25D91C08@webmail.messagingengine.com> <mailman.422.1462498634.32212.python-list@python.org> <ngh0hu$4og$1@dont-email.me> <ngh1pb$4og$2@dont-email.me> <CAPTjJmpiBP3hDSZrzX8YQZFC-0G3OM_ZVg3yfpG+MNv9B7S_OA@mail.gmail.com>

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On Fri, May 6, 2016 at 1:07 PM, Dan Sommers <dan@tombstonezero.net> wrote:
> On Fri, 06 May 2016 02:46:22 +0000, Dan Sommers wrote:
>
>>     Python 2.7.11+ (default, Apr 17 2016, 14:00:29)
>>     [GCC 5.3.1 20160409] on linux2
>>     Type "help", "copyright", "credits" or "license" for more information.
>>     >>> filter(lambda x:x+1, [1, 2, 3, 4])
>>     [1, 2, 3, 4]
>>
>>     Python 3.5.1+ (default, Apr 17 2016, 16:14:06)
>>     [GCC 5.3.1 20160409] on linux
>>     Type "help", "copyright", "credits" or "license" for more information.
>>     >>> filter(lambda x:x+1, [1, 2, 3, 4])
>>     <filter object at 0x7f26a9ef3320>
>
> Muphrey's Law strikes again.  That lambda function is obviously a
> leftover from a call to *map* rather than a call to *filter*, but thanks
> everyone for not laughing and pointing.

Hey, maybe you wanted to filter out all the -1 results. Maybe you have
a search function that returns zero-based offsets, or -1 for "not
found". Seems reasonable! And "x+1" is way shorter than "x!=-1", which
means by definition that it's better.

ChrisA

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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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