Re: Simple map/reduce utility function for data analysis

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From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	comp.lang.python
Subject	Re: Simple map/reduce utility function for data analysis
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Date	Mon, 25 Apr 2011 19:42:17 -0700
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Raymond Hettinger <python@rcn.com> writes:
> Here's a handy utility function for you guys to play with:
>     http://code.activestate.com/recipes/577676/

Cute, but why not use collections.defaultdict for the return dict?
Untested:

   d = defaultdict(list)
   for key,value in ifilter(bool,imap(mapper, data)):
      d[key].append(value)
   ...

Thread

Simple map/reduce utility function for data analysis Raymond Hettinger <python@rcn.com> - 2011-04-25 16:48 -0700
  Re: Simple map/reduce utility function for data analysis Paul Rubin <no.email@nospam.invalid> - 2011-04-25 19:42 -0700
    Re: Simple map/reduce utility function for data analysis Raymond Hettinger <python@rcn.com> - 2011-04-26 11:12 -0700
  Re: Simple map/reduce utility function for data analysis Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2011-04-26 02:52 +0000

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