Does '!=' equivelent to 'is not'

[Leo Jay]

On Tue, Jun 17, 2008 at 11:29 AM, pirata <pirata at mars.invalid> wrote:
> I'm a bit confusing about whether "is not" equivelent to "!="
>
> if a != b:
>  ...
>
> if a is not b:
>  ...
>
>
> What's the difference between "is not" and "!=" or they are the same thing?

The 'is' is used to test do they point to the exactly same object.
The '==' is used to test are their values equal.

same objects are equal, but equal don't have to be the same object.

and be very careful to the dirty corner of python:
>>> a = 100000
>>> b = 100000
>>> a is b
False
>>> a == b
True
>>> a = 5
>>> b = 5
>>> a is b
True
>>> a == b
True
>>>

which is caused by small object cache mechanism.


-- 
Best Regards,
Leo Jay