Python's super() Useful Feature

After presenting the latest Packet Coders tech session in our membership last night, around Python OOP (recording here) there was one feature that I wanted to share with you, that is super useful for preventing code duplication when working with Python classes.

This feature (technically a Python method) is called super(). The TL;DR here is super():

is used to provide access to methods and properties of a parent class.

In other words, let's say we have a Router object. Like so:

class Router:
    def __init__(self, vendor, platform):
        self.vendor = vendor
        self.platform = platform

Let's say we want to create an Mx object which also includes a site attribute.
We could do this, but as you can see, we are duplicating code.

class Mx(Router):
    def __init__(self, vendor, platform, site):
        self.vendor = vendor      <--- code duplication
        self.platform = platform  <--- code duplication
        self.site = site

Instead, we can use super(), like so, to access these attributes from the parent class.

class Mx(Router):
    def __init__(self, vendor, platform, site):
        super().__init__(vendor, platform)
        self.site = site

We can now create an instance of our Mx object like so:

>>> r2 = Mx(vendor="juniper", platform="mx", site="london")
>>> print(r2.site)
london

Good stuff!