idiom for initial list of lists
Tim Hochberg
tim.hochberg at ieee.org
Fri Sep 8 15:55:14 EDT 2000
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([])
Here's another way, although it's only practical if your already using NumPy.
S = Numeric.zeros([5,0]).tolist()
-tim
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