list of empty lists

[Curtis Jensen]

Is there a easy way to make a list of an arbitray number of empty lists?

I can do something like:
 >>> some_number = 3
 >>> l = [[]] * some_number
 >>> l
[[], [], []]

Unfortunatly this has an unfortunate side affect.  Whatever I do to one 
of the list gets done to the other lists. ie:
 >>> l[0].append(1)
 >>> l
[[1], [1], [1]]


In this case, what I would like is three independantly empty lists.  I 
can make a for loop to loop "some_number" of times and append an empty 
list at each itteration.  Is there a simpler way?
Thanks.

-- 
Curtis Jensen
cjensen at bioeng.ucsd.edu
http://www-bioeng.ucsd.edu/~cjensen/
FAX (425) 740-1451