Python: How to add a custom function to a pre-existing object?

Question

Is it possible to add your own custom function to an already existing object?

For example, the 'string' datatype has no built-in reverse() function unlike in a list , is there a way to add a reverse function such that if I have a string variable var , var.reverse() returns the string in reverse?

One way I think this would work is if I create a class CustomString that has the same properties as a string but with an additional defined reverse function, is this possible? (I'm not yet familiar with Python OOP)

Or is there another way of doing this?

Answer 1

You could do this using inheritance:

class new_string(str):
    def reverse(self):
        blah

s = new_string('hello')
s.reverse()

EDIT: Does your code look like this:

>>> class S(str):
...     def reverse(self):
...         return self.__str__()[::-1]
... 
>>> s = S('hello')
>>> s.reverse()
'olleh'