[Tutor] listing all combinations of elements of a list
Bill Kranec
billk at fastmail.fm
Sun Dec 12 21:51:56 CET 2004
Is there a module containing a function for listing the unique k-element
subsets of an n-item list? I have written some code (right now I only
need it for 2 element subsets):
def combination(items)
list = []
for i in range(0,len(items)):
for j in range(0,len(items)):
if j > i:
list.append((list[i],list[j]))
return list
My problems with this code being that a) code I write is usually pretty
inefficient, b) it doesn't extend to subsets of size > 2, and c) it uses
nested loops, which I have gathered from some previous discussions on
this list to be less than ideal.
Any thoughts on how to improve / replace this code would be appreciated.
Thanks,
Bill
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