Re: a better way to invert a list?

From	Raymond Hettinger <python@rcn.com>
Newsgroups	comp.lang.python
Subject	Re: a better way to invert a list?
Date	2011-04-05 17:07 -0700
Organization	http://groups.google.com
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References	<2215eefd-3677-4459-8656-aa04978f6f3f@g7g2000pro.googlegroups.com> <mailman.61.1302039998.9059.python-list@python.org>

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[Ian Kelly]
> Which is O(n).  If that is too verbose, you could also use a dictionary:
>
> def invert(p):
>     return dict(map(reversed, enumerate(p)))


def inv(p):
    return dict(zip(p, itertools.count()))


Raymond

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a better way to invert a list? scattered <tooscattered@gmail.com> - 2011-04-05 14:17 -0700
  Re: a better way to invert a list? Ian Kelly <ian.g.kelly@gmail.com> - 2011-04-05 15:46 -0600
    Re: a better way to invert a list? scattered <tooscattered@gmail.com> - 2011-04-05 16:24 -0700
      Re: a better way to invert a list? Glazner <yoavglazner@gmail.com> - 2011-04-06 01:48 -0700
        Re: a better way to invert a list? scattered <tooscattered@gmail.com> - 2011-04-06 02:48 -0700
        Re: a better way to invert a list? Peter Otten <__peter__@web.de> - 2011-04-06 11:58 +0200
    Re: a better way to invert a list? Raymond Hettinger <python@rcn.com> - 2011-04-05 17:07 -0700
  Re: a better way to invert a list? Paul Rubin <no.email@nospam.invalid> - 2011-04-06 12:51 -0700
    Re: a better way to invert a list? Ian Kelly <ian.g.kelly@gmail.com> - 2011-04-06 14:08 -0600

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