For the same reason that def f(z): z *= z c = 1 f(c) print c prints 1. Jeff -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 196 bytes Desc: not available URL: <http://mail.python.org/pipermail/python-list/attachments/20050924/0fa4d290/attachment.sig>