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Re: unzip function?

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From	Hrvoje Niksic <hniksic@xemacs.org>
Newsgroups	comp.lang.python
Subject	Re: unzip function?
Date	Wed, 18 Jan 2012 19:01:10 +0100
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Neal Becker <ndbecker2@gmail.com> writes:

> python has builtin zip, but not unzip
>
> A bit of googling found my answer for my decorate/sort/undecorate problem:
>
> a, b = zip (*sorted ((c,d) for c,d in zip (x,y)))
>
> That zip (*sorted...
>
> does the unzipping.
>
> But it's less than intuitively obvious.
>
> I'm thinking unzip should be a builtin function, to match zip.

"zip" and "unzip" are one and the same since zip is inverse to itself:

>>> [(1, 2, 3), (4, 5, 6)]
[(1, 2, 3), (4, 5, 6)]
>>> zip(*_)
[(1, 4), (2, 5), (3, 6)]
>>> zip(*_)
[(1, 2, 3), (4, 5, 6)]
>>> zip(*_)
[(1, 4), (2, 5), (3, 6)]

What you seem to call unzip is simply zip with a different signature,
taking a single argument:

>>> def unzip(x):
...   return zip(*x)
...
>>> [(1, 2, 3), (4, 5, 6)]
[(1, 2, 3), (4, 5, 6)]
>>> unzip(_)
[(1, 4), (2, 5), (3, 6)]
>>> unzip(_)
[(1, 2, 3), (4, 5, 6)]
>>> unzip(_)
[(1, 4), (2, 5), (3, 6)]

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Thread

unzip function? Neal Becker <ndbecker2@gmail.com> - 2012-01-18 09:33 -0500
  Re: unzip function? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-18 15:27 +0000
    Re: unzip function? Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-18 11:20 -0500
      Re: unzip function? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-18 23:20 +0000
        Re: unzip function? Devin Jeanpierre <jeanpierreda@gmail.com> - 2012-01-19 10:56 -0500
        RE: unzip function? "Prasad, Ramit" <ramit.prasad@jpmorgan.com> - 2012-02-03 00:53 +0000
  Re: unzip function? Hrvoje Niksic <hniksic@xemacs.org> - 2012-01-18 19:01 +0100

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