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Surprise using the 'is' operator

Georg Brandl g.brandl-nospam at gmx.net
Wed Sep 27 12:39:39 EDT 2006 
tobiah wrote:
>>> Suppose I fill an list with 100 million random integers in the range
>>> of 1 - 65535.  Wouldn't I save much memory if all of the ocurrances
>>> of '12345' pointed to the same integer object?  Why should more be made,
>>> when they all do the same thing, and are not subject to change?
>> 
>> Because for typical usage of integers (which doesn't include your example),
>> it is more expensive to check if there's already an integer with that 
>> specific
>> value out there than to create a new one.
>> 
>> 
>> Georg
> 
> I see.  I assume then, that the lookup performance hit is acceptable
> as a trade off against memory usage for the quite commonly used range
> of (-5, 257).  Is that the idea?

Yes, indeed.

Georg
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