what is the keyword "is" for?

[Steve Holden]

daniel wrote:
> Martin v. Löwis wrote:
[...]
>>For some objects, "change the object" is impossible. If you have
>>
>>a = b = 3
>>
>>then there is no way to change the object 3 to become 4 (say);
>>integer objects are "immutable". So for these, to make a change,
>>you really have to change the variable, not the value.
>>
> 
> sounds reasonable, I tried tuple which is also immutable, it behaves
> the same as integers. 
> 
Well spotted. Tuples are indeed immutable, as are strings, unicode 
strings, integers and floats.

regards
  Steve
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