GeezerVison

This article describes how Python string interning works in CPython 2.7.7.

A few days ago, I had to explain to a colleague what the built-in function intern does. I gave him the following example:

>>> s1 = 'foo!'
>>> s2 = 'foo!'
>>> s1 is s2
False
>>> s1 = intern('foo!')
>>> s1
'foo!'
>>> s2 = intern('foo!')
>>> s1 is s2
True