Initializing a list of lists

tkpmep at hotmail.com tkpmep at hotmail.com
Sun Mar 19 16:29:00 CET 2006


I want to create a list of lists, each of which is identical, but which
can be modified independently i.e:

>>>x = [ [0], [0], [0] ]
>>> x[0].append(1)
>>> x
[[0, 1], [0], [0]]

The above construct works if I have only few items, but if I have many,
I'd prefer to write
>>> N =3
>>> x =N*[[0]]
>>> x
[[0], [0], [0]]

If I now try extending the lists indepently, I cannot, as they all
point to the same list object
>>> x[0].append(1)
>>> x
[[0, 1], [0, 1], [0, 1]]

Is there a simple way to create a list of independent lists?

Thanks in advance

Thomas Philips




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