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To: python-list@python.org
From: Ned Deily <nad@acm.org>
Subject: Re: pairwise combination of two lists
Date: Wed, 17 Aug 2011 14:33:17 -0700
References: <98CC6556-11F3-4850-BD2B-30481B53042D@mssm.edu>
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:11717

In article <98CC6556-11F3-4850-BD2B-30481B53042D@mssm.edu>,
 Yingjie Lin <Yingjie.Lin@mssm.edu> wrote:
> I have two lists: 
> 
> li1 = ['a', 'b']
> li2 = ['1', '2']
> 
> and I wish to obtain a list like this
> 
> li3 = ['a1', 'a2', 'b1', 'b2']
> 
> Is there a handy and efficient function to do this, especially when li1 and 
> li2 are long lists.
> I found zip() but it only gives [('a', '1'), ('b', '2')],  not exactly what I 
> am looking for.

>>> from itertools import product
>>> li1 = ['a', 'b']
>>> li2 = ['1', '2']
>>> li3 = list("".join(x) for x in product(li1, li2))
>>> li3
['a1', 'a2', 'b1', 'b2']

-- 
 Ned Deily,
 nad@acm.org