Concatenating a list of lists

Stas Z. stas at linux.isbeter.nl
Sun Aug 18 10:25:25 CEST 2002


On Sun, 18 Aug 2002 02:56:07 +0200, Wojtek Walczak wrote:

> Dnia 17 Aug 2002 13:17:19 -0700, Neophytos Michael napisa³(a):
>> A quick question for the python experts.  I have a list of lists (only
>> one level) that I want to turn into a flat list.  What's the python way
>> of achieving this?  I came up with:
> 
>>>> a = [ range(1,5), range(5,10) ]
>>>> a
> [[1, 2, 3, 4], [5, 6, 7, 8, 9]]
>>>> b=[]
>>>> [b.extend(i) for i in a]

For speed:
>>> map(b.extend,a)

IMHO, this is also more pythonisch. -)

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