On Fri, 05 Apr 2013 06:49:14 -0700, Candide Dandide wrote: > So, could someone please explain what exactly the is operator returns ? > The official doc says : > > The ‘is‘ operator compares the identity of two objects; the id() > function returns an integer representing its identity (currently > implemented as its address).
The docs are correct. But an identity is only unique for the lifetime of the object, so "x is y" and "id(x)==id(y)" are only equivalent if the lifetimes of x and y overlap. If the objects have disjoint lifetimes (i.e. one is created after the other has been destroyed), then it's possible for id() to return the same value for both objects, so id(x)==id(y) can return a "false positive" result, as happened in your example. -- http://mail.python.org/mailman/listinfo/python-list
