On May 14, 9:39 am, Terry Reedy <tjre...@udel.edu> wrote: > On 5/14/2010 11:24 AM, gerardob wrote: > > > > > Hello, let S be a python set which is not empty > > (http://docs.python.org/library/sets.html) > > > i would like to obtain one element (anyone, it doesn't matter which one) and > > assign it to a variable. > > > How can i do this? > > Depends on whether or not you want the element removed from the set > > #3.1 > >>> s=set(range(10)) > >>> s > {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} > >>> x=next(iter(s)) > >>> x > 0 > >>> s > {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} # x not removed > >>> x = s.pop() > >>> x > 0 > >>> s > {1, 2, 3, 4, 5, 6, 7, 8, 9} # x has been removed > > The choice of 0 is an implementation artifact. It could have been any > member.
Which brings up an interesting question: how do you get a random element from a set? random.choice(list(s)) is the most straightforward way and will work a lot of the time, but how would you avoid creating the list? I can't think of a way off hand. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
