How to extend a class in python?

python class interface
omega picture omega · Mar 20, 2013 · Viewed 125.3k times · Source

In python how can you extend a class? For example if I have

color.py

class Color:
    def __init__(self, color):
        self.color = color
    def getcolor(self):
        return self.color

color_extended.py

import Color

class Color:
    def getcolor(self):
        return self.color + " extended!"

But this doesn't work... I expect that if I work in color_extended.py, then when I make a color object and use the getcolor function then it will return the object with the string " extended!" in the end. Also it should have gotton the init from the import.

Assume python 3.1

Thanks

Answer

NPE picture NPE · Mar 20, 2013

Use:

import color

class Color(color.Color):
    ...

If this were Python 2.x, you would also want to derive color.Color from object, to make it a new-style class:

class Color(object):
    ...

This is not necessary in Python 3.x.

Related questions

What is the purpose of checking self.__class__ ? - python

What is the purpose of checking self.__class__ ? I've found some code that creates an abstract interface class and then checks whether its self.__class__ is itself, e.g. class abstract1 (object): def __init__(self): if self.__class__ == abstract1: raise …

Read More
Understanding Python super() with __init__() methods

I'm trying to understand the use of super(). From the looks of it, both child classes can be created, just fine. I'm curious to know about the actual difference between the following 2 child classes. class Base(object): def __init__(self): …

Read More
Are static class variables possible in Python?

Is it possible to have static class variables or methods in Python? What syntax is required to do this?

Read More