[Python-Dev] redefining is

[Guido van Rossum]

> Here is a real life example where "is" on immutable objects is very 
> helpful for perfomance reasons

I apreciate that 'is' is faster than '==' for comparing two strings of
length 500, but have you tried to measure how much time you are saving
in your application?

I doubt it's in the noise.  And unless the intern()ed strings are
compared over and over, the cost of intern() is mroe than the savings
in comparison.

(The best scheme is probably to use intern() but still use '==' for
comparisons; '==' is smart enough to skip comparing an object to
itself.)

--Guido van Rossum (home page: http://www.python.org/~guido/)