Am I wrong, or is that what the module sets is for? I don't remember if python 2.3 has it, but python2.4 has it available.
>>> import sets >>> s = sets.Set >>> a = s([1,2,3]) >>> a Set([1, 2, 3]) >>> a.update([1,1,2,2,3,3,4,4,5,5]) >>> a Set([1, 2, 3, 4, 5]) >>> HTH, Jacob Schmidt > > def combination(items) > > list = [] > > for i in range(0,len(items)): > > for j in range(0,len(items)): > > for i in items: > for j in items: > > Is both shorter and faster - no len() function calls. > > Or if you want to use indices: > > size = len(items) # only calculate once, it won't change! > lst = [] # don't use builtin function names for > variables > for i in range(0,size) > for j in range(i+1,size) > lst.append(....) > return lst > > That saves a lot of len() calls and a comparison. > Also it avoids iterating over the whole list each time. > > > > 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. > > I've tidied up a little but I think nested loops are a necessary evil > in > this case - although somebody is sure to prove me wrong! :-) > > HTH, > > Alan G. > > _______________________________________________ > Tutor maillist - [EMAIL PROTECTED] > http://mail.python.org/mailman/listinfo/tutor > > _______________________________________________ Tutor maillist - [EMAIL PROTECTED] http://mail.python.org/mailman/listinfo/tutor
