On Jun 1, 8:28�pm, Steven D'Aprano <st...@remove-this- cybersource.com.au> wrote: > On Mon, 01 Jun 2009 17:24:49 -0700, Mensanator wrote: > > On Jun 1, 6:40�pm, Steven D'Aprano <st...@remove-this- > > cybersource.com.au> wrote: > >> On Mon, 01 Jun 2009 11:23:35 -0700, Mensanator wrote: > >> > I believe the name you're looking for is > >> > combinations_with_replacement. It is one of the features being added > >> > to 3.1 which should give all the subsets of the Cartesian Product: > > >> > permutations_with_replacement: � �product() > >> > combinations_with_replacement: � �combinations_with_replacement() > >> > permutations_without_replacement: permutations() > >> > combinations_without_replacement: combinations() > > >> What, no partitions? > > > Itertools does partitions? > > Er, no. That's why I asked "What, no partitions?" instead of saying > "Look, itertools also does partitions!" > > >>http://en.wikipedia.org/wiki/Partition_of_a_set > > > I didn't see any reference to Cartesian Product there. > > Wikipedia is the encyclopedia anyone can edit. Go right ahead and put it > in if you think it needs to be there. While you're at it, there is no > mention of Cartesian Product in any of > > http://en.wikipedia.org/wiki/Permutationshttp://en.wikipedia.org/wiki/Combinations > > http://mathworld.wolfram.com/Permutation.htmlhttp://mathworld.wolfram.com/k-Subset.html > > either.
You might have better luck with Google. > Are you sure that permutations and combinations are subsets of > the Cartesian Product? Sure looks that way (SQL examples): Cartesian Product (Permutaions w/replacement) SELECT B.q, A.p FROM A, B; q p a a a b b a b b Permutaions wo/replacement SELECT B.q, A.p FROM A, B WHERE (((A.p)<>[B].[q])); q p a b b a Combinations w/replacement SELECT B.q, A.p FROM A, B WHERE (((A.p)>=[B].[q])); q p a a a b b b Combinations wo/replacement SELECT B.q, A.p FROM A, B WHERE (((A.p)>[B].[q])); q p a b I couldn't do that if they weren't subsets. > > -- > Steven -- http://mail.python.org/mailman/listinfo/python-list
