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 small numbers, Python is reusing the object instances, but for larger numbers, it creates new instances for them.

See this:

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

>>> id(a)
158013588
>>> id(b)
158013588
>>> id(c)
158151472
>>> id(d)
158151436

which is exactly why a is b, but c isn't d.