Save Time When Writing Python Classes

Today I`m going to quickly show you how you can save a bunch of time and code when writing classes.

Typically when writing a class we do something like this.

class Interface:
    def __init__(self, name: str, speed: int, mtu: int) -> None:
        self.name = name
        self.speed = speed
        self.mtu = mtu
        
    def __str__(self):
        return "__str__"
        
    def __repr__(self):
        return "__repr__"
        
    def __eq__(self, other):
        return True

# Create instance
>>> rtr_interface = Interface(name="gi0/1", speed="1000", mtu="1500")

# Show instance representation (`__repr__`)
>>> rtr_interface
'__repr'

# Show string representation of instance (`__str__`)
>>> print(rtr_interface)
'__str__'

# Perform equal based comparision
>>> rtr_interface == rtr_interface
True

The main point here is that we need some code for the instance creation (__init__) and assigning the variables at instantiation, along with having to assign the other special methods such as __repr__, __str__ and __eq__.

Let me introduce you to Data Classes, in short,

... data classes reduce the amount of boiler plate code required when writing classes. By default a data class will generate the special methods init, repr, str and eq for you.

For example:

from dataclasses import dataclass

@dataclass
class Interface:
    name: str
    speed: int
    mtu: int

>>> rtr_interface = Interface(name="gi0/1", speed="1000", mtu="1500")

>>> rtr_interface
Interface(name='gi0/1', speed='1000', mtu='1500')

>>> print(rtr_interface)
Interface(name='gi0/1', speed='1000', mtu='1500')

>>> rtr_interface == rtr_interface
True

Cool, right! Data Classes can do a ton of other stuff as well which is covered below in more detail: