easy question on parsing python: "is not None"

Steven D'Aprano steve at REMOVE-THIS-cybersource.com.au
Sat Aug 7 00:28:52 CEST 2010


On Fri, 06 Aug 2010 15:37:04 +0200, Stefan Schwarzer wrote:

>> Plus, I believe the
>> "==" operator will check if the variables point to the same object.
> 
> No, that's what `is` is for.

Actually, yes, equality is implemented with a short-cut that checks for 
identity first. That makes something like:

s = "abc"*1000*1000*10
s == s

nice and quick, as Python can immediately recognise that a string is 
always equal to itself without having to walk the entire string comparing 
each character with itself.



-- 
Steven



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