Confused about `is` operator with strings

Question

The is operator compares the memory addresses of two objects, and returns True if they\'re the same. Why, then, does it not work reliably with stri

Answer 1

Note that this is a CPython specific optimization. If you want your code to be portable, you should avoid it. For example, in PyPy

>>>> a = "hi"
>>>> b = "hi"
>>>> a is b
False

It's also worth pointing out that a similar thing happens for small integers

>>> a = 12
>>> b = 12
>>> a is b
True

which again you should not rely on, because other implementations might not include this optimization.