Strange Python behavior from inappropriate usage of 'is not' comparison?

Question

I (incorrectly?) used \'is not\' in a comparison and found this curious behavior:

>>> a = 256
>>> b = int(\'256\')
>>> c = 300
>>         


        

Answer 1

For more understanding why this occurs take a look to Python-2.6.5/Objects/intobject.c:78:small_ints array and Python-2.6.5/Objects/intobject.c:1292:_PyInt_Init function in python sources.

Also similar thing occurs with lists:

>>> a = [12]
>>> id_a = id(a)
>>> del(a)
>>> id([1,2,34]) == id_a
True
>>> 

Removed lists are not destroyed. They are reused