vdrab wrote: > I guess the take-away lesson is to steer clear from any reliance on > object identity checks, if at all possible.
BINGO! > Are there any other such > "optimizations" one should like to know about? You don't have to know about them, as long as you use the operators correctly. == tests equality. is tests identity. Use is ONLY when you are testing whether two things are the same object. Otherwise, use ==. When deciding which operator to use, ask yourself this: would the result still be true if they were different objects with the same value? If yes, then use ==. 0 == 0 should be true even if the two zeros are different objects. Corrollary: You should test for singleton objects with is. None, NotImplemented, and Ellipsis are singleton objects; this is part of the language and not an implementation detail. You can rely on it. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
