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Re: Good use for itertools.dropwhile and itertools.takewhile

From Neil Cerutti <neilc@norwich.edu>
Newsgroups comp.lang.python
Subject Re: Good use for itertools.dropwhile and itertools.takewhile
Date 2012-12-04 18:26 +0000
Organization Norwich University
Message-ID <ai6thvFo9u6U1@mid.individual.net> (permalink)
References <b80f3ab3-ef81-4806-86db-efd5800d4bb3@googlegroups.com> <mailman.461.1354631511.29569.python-list@python.org> <mailman.465.1354635214.29569.python-list@python.org>

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On 2012-12-04, Nick Mellor <thebalancepro@gmail.com> wrote:
> I love the way you guys can write a line of code that does the
> same as 20 of mine :)
>
> I can turn up the heat on your regex by feeding it a null
> description or multiple white space (both in the original
> file.) I'm sure you'd adjust, but at the cost of a more complex
> regex.

A re.split should be able to handle this without too much hassle.

The simplicity of my two-line version will evaporate pretty
quickly to compensate for edge cases.

Here's one that can handle one of the edge cases you mention, but
it's hardly any shorter than what you had, and it doesn't
preserve non-standard whites space, like double spaces.

def prod_desc(s):
    """split s into product name and product description. Product
    name is a series of one or more capitalized words followed
    by white space. Everything after the trailing white space is
    the product description.

    >>> prod_desc("CAR FIFTY TWO Chrysler LeBaron.")
    ['CAR FIFTY TWO', 'Chrysler LeBaron.']
    """
    prod = []
    desc = []
    target = prod
    for word in s.split():
        if target is prod and not word.isupper():
            target = desc
        target.append(word)
    return [' '.join(prod), ' '.join(desc)]

When str methods fail I'll usually write my own parser before
turning to re. The following is no longer nice looking at all.

def prod_desc(s):
    """split s into product name and product description. Product
    name is a series of one or more capitalized words followed
    by white space. Everything after the trailing white space is
    the product description.

    >>> prod_desc("CAR FIFTY TWO Chrysler LeBaron.")
    ['CAR FIFTY TWO', 'Chrysler LeBaron.']

    >>> prod_desc("MR.  JONESEY   Saskatchewan's finest")
    ['MR.  JONESEY', "Saskatchewan's finest"]
    """
    i = 0
    while not s[i].islower():
        i += 1
    i -= 1
    while not s[i].isspace():
        i -= 1
    start_desc = i+1
    while s[i].isspace():
        i -= 1
    end_prod = i+1
    return [s[:end_prod], s[start_desc:]]

-- 
Neil Cerutti

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Thread

Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-04 05:57 -0800
  Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-04 14:23 +0000
    Re: Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-04 06:47 -0800
      Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-04 15:17 +0000
  Re: Good use for itertools.dropwhile and itertools.takewhile Vlastimil Brom <vlastimil.brom@gmail.com> - 2012-12-04 15:31 +0100
    Re: Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-04 07:24 -0800
      Re: Good use for itertools.dropwhile and itertools.takewhile Vlastimil Brom <vlastimil.brom@gmail.com> - 2012-12-04 22:08 +0100
    Re: Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-04 07:24 -0800
      Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-04 18:26 +0000
  Re: Good use for itertools.dropwhile and itertools.takewhile Alexander Blinne <news@blinne.net> - 2012-12-04 18:18 +0100
    Re: Good use for itertools.dropwhile and itertools.takewhile DJC <djc@news.invalid> - 2012-12-04 18:28 +0000
      Re: Good use for itertools.dropwhile and itertools.takewhile Alexander Blinne <news@blinne.net> - 2012-12-04 19:48 +0100
        Re: Good use for itertools.dropwhile and itertools.takewhile Ian Kelly <ian.g.kelly@gmail.com> - 2012-12-04 12:37 -0700
          Re: Good use for itertools.dropwhile and itertools.takewhile Alexander Blinne <news@blinne.net> - 2012-12-04 21:33 +0100
          Re: Good use for itertools.dropwhile and itertools.takewhile Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-04 21:13 +0000
        Re: Good use for itertools.dropwhile and itertools.takewhile MRAB <python@mrabarnett.plus.com> - 2012-12-04 20:17 +0000
  Re: Good use for itertools.dropwhile and itertools.takewhile Terry Reedy <tjreedy@udel.edu> - 2012-12-04 15:44 -0500
    Re: Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-04 17:17 -0800
      Re: Good use for itertools.dropwhile and itertools.takewhile Chris Angelico <rosuav@gmail.com> - 2012-12-06 00:45 +1100
        Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-05 14:34 +0000
          Re: Good use for itertools.dropwhile and itertools.takewhile Ian Kelly <ian.g.kelly@gmail.com> - 2012-12-05 08:33 -0700
            Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-05 16:11 +0000
      Re: Good use for itertools.dropwhile and itertools.takewhile Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-12-05 15:32 +0000
      Re: Good use for itertools.dropwhile and itertools.takewhile Ian Kelly <ian.g.kelly@gmail.com> - 2012-12-05 09:16 -0700
      Re: Good use for itertools.dropwhile and itertools.takewhile MRAB <python@mrabarnett.plus.com> - 2012-12-05 17:57 +0000
    Re: Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-04 17:17 -0800
      Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-05 13:29 +0000
        Re: Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-05 09:04 -0800
          Re: Good use for itertools.dropwhile and itertools.takewhile MRAB <python@mrabarnett.plus.com> - 2012-12-05 17:57 +0000
          Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-05 18:16 +0000
            Re: Good use for itertools.dropwhile and itertools.takewhile Nick Mellor <thebalancepro@gmail.com> - 2012-12-05 11:01 -0800
              Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-05 20:13 +0000
              Re: Good use for itertools.dropwhile and itertools.takewhile Vlastimil Brom <vlastimil.brom@gmail.com> - 2012-12-05 22:36 +0100
                Re: Good use for itertools.dropwhile and itertools.takewhile Neil Cerutti <neilc@norwich.edu> - 2012-12-06 13:06 +0000
                Re: Good use for itertools.dropwhile and itertools.takewhile Vlastimil Brom <vlastimil.brom@gmail.com> - 2012-12-06 15:12 +0100
          Re: Good use for itertools.dropwhile and itertools.takewhile Alexander Blinne <news@blinne.net> - 2012-12-06 14:40 +0100
  Re: Good use for itertools.dropwhile and itertools.takewhile Terry Reedy <tjreedy@udel.edu> - 2012-12-04 17:21 -0500
  Re: Good use for itertools.dropwhile and itertools.takewhile Paul Rubin <no.email@nospam.invalid> - 2012-12-06 13:29 -0800

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