idiom for initial list of lists

Robin Becker robin at jessikat.fsnet.co.uk
Sat Sep 9 00:53:19 CEST 2000


In article <wkem2uixcq.fsf at turangalila.harmonixmusic.com>, Dan Schmidt
<dfan at harmonixmusic.com> writes
>Robin Becker <robin at jessikat.fsnet.co.uk> writes:
>
>| What's the correct way to initialise a list of lists I find that the
>| natural [[]]*n doesn't work eg
>| >>> S=[[]]*5
>| >>> S
>| [[], [], [], [], []]
>| >>> S[0].append(1)
>| >>> S
>| [[1], [1], [1], [1], [1]]
>| 
>| so I'm forced to use the rather pedantic
>| S=[]
>| for i in range(n): S[i].append([])
>
>How about
>
>  S = map (lambda x : [], range(5))
>
>Or in Python 2.0,
>
>  S = [[] for x in range(5)]
>
far too new for oflm
-- 
Robin Becker



More information about the Python-list mailing list