I think the OP wants to find the intersection of two lists. list(set(list1) & set(list2)) is indeed one way to achieve this. [i for i in list1 if i in list2] is another one.
Sigmund On May 15, 4:11 am, Chris Torek <nos...@torek.net> wrote: > In article <871v00j2bh....@benfinney.id.au> > Ben Finney <ben+pyt...@benfinney.id.au> wrote: > > >As pointed out: you already know how to create a set from an object; > >creating a list from an object is very similar: > > > list(set(aa)) > > >But why are you doing that? What are you trying to achieve? > > I have no idea why someone *else* is doing that, but I have used > this very expression to unique-ize a list: > > >>> x = [3, 1, 4, 1, 5, 9, 2, 6] > >>> x > [3, 1, 4, 1, 5, 9, 2, 6] > >>> list(set(x)) > [1, 2, 3, 4, 5, 6, 9] > >>> > > Of course, this trick only works if all the list elements are > hashable. > > This might not be the best example since the result is sorted > "by accident", while other list(set(...)) results are not. Add > sorted() or .sort() if needed: > > >>> x = ['three', 'one', 'four', 'one', 'five'] > >>> x > ['three', 'one', 'four', 'one', 'five'] > >>> list(set(x)) > ['four', 'five', 'three', 'one'] > >>> sorted(list(set(x))) > ['five', 'four', 'one', 'three'] > >>> > -- > In-Real-Life: Chris Torek, Wind River Systems > Salt Lake City, UT, USA (40°39.22'N, 111°50.29'W) +1 801 277 2603 > email: gmail (figure it out) http://web.torek.net/torek/index.html -- http://mail.python.org/mailman/listinfo/python-list
