On Wed, 17 Aug 2011 20:08:23 -0700 (PDT), Emily Anne Moravec wrote: > I want to add 5 to each element of a list by using a for loop. > > Why doesn't this work? > > numbers = [1, 2, 3, 4, 5] > for n in numbers: > n = n + 5 > print numbers
Because integers are immutable. You cannot turn 1 into 6. Contrast this behavior with lists, which *are* mutable: >>> numbers = [[1],[2],[3],[4],[5]] >>> for n in numbers: ... n[0]= n[0] + 5 ... >>> numbers [[6], [7], [8], [9], [10]] For practical purposes, I'm sure you'll find other responders' excellent posts to be of more immediate use, but keeping mutability in mind helps. -- To email me, substitute nowhere->spamcop, invalid->net. -- http://mail.python.org/mailman/listinfo/python-list
