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From: Peter Otten <__peter__@web.de>
Subject: Re: Insert item before each element of a list
Date: Mon, 08 Oct 2012 23:12:07 +0200
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Xref: csiph.com comp.lang.python:30973

mooremathewl@gmail.com wrote:

> What's the best way to accomplish this?  Am I over-complicating it?  My
> gut feeling is there is a better way than the following:
> 
>>>> import itertools
>>>> x = [1, 2, 3]
>>>> y = list(itertools.chain.from_iterable(('insertme', x[i]) for i in
>>>> range(len(x)))) y
> ['insertme', 1, 'insertme', 2, 'insertme', 3]

Less general than chain.from_iterable(izip(repeat("insertme"), x)):

>>> x = [1, 2, 3]
>>> y = 2*len(x)*["insertme"]
>>> y[1::2] = x
>>> y
['insertme', 1, 'insertme', 2, 'insertme', 3]