On Fri, Apr 6, 2012 at 4:44 AM, Michael Hrivnak <mhriv...@hrivnak.org> wrote: > This is not a gotcha, and it's not surprising. As John described, > you're assigning a new value to an index of a tuple, which tuples > don't support. > > a[0] += [3] > > is the same as > > a[0] = a[0] + [3] > > which after evaluation is the same as > > a[0] = [1, 3] > > You can always modify an item that happens to be in a tuple if the > item itself is mutable, but you cannot add, remove, or replace items > in a tuple.
It does make sense, and I've never actually had problems with it myself. But it's come up on the list and clearly been a cause of confusion for people, so I thought it worth mentioning. And, as it turns out, it was the entry already on the list. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
