On Mar 10, 10:39 am, Gary Herron <[EMAIL PROTECTED]> wrote: > Metal Zong wrote: > > > The operator is and is not test for object identity: x is y is true if > > and only if x and y are the same objects. > > > >>> x = 1 > > > >>> y = 1 > > > >>> x is y > > > True > > > Is this right? Why? Thanks. > > Yes that is true, but it's an implementation defined optimization and > could be applied to *any* immutable type. For larger ints, such a thing > is not true. > >>> x=1000 > >>> y=1000 > >>> x is y > False > > If either is a surprise, then understand that the "is" operator should > probably *never* be used with immutable types.
Not quite: None is immutable but it's usually recommended to test for it using is. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
