Question

I am currently writing my python classes and instantiate them like this

class calculations_class():
    def calculate(self):
        return True

Calculations = calculations_class()

I was wondering if I was doing this correctly, or if there were any other ways to instantiate them. Thanks!

Answer 1

Apart from the naming convention issue which other answers have correctly pointed out, you’re basically fine: calling a class is indeed by far the most common way of instantiating that class. If you need any per-instance initialization (most typically setting some instance-attributes to initial values), be sure to define an __init__ method that performs it:

class Calculations(object):
  def __init__(self):
    self.running_total = 0  # or w/ever
  def calculate(self):
    ...

calc = Calculations()

The other, rare ways of instantiating a class typically occur when you want to bypass the initialization part for some reason (e.g., in the course of de-serializing an instance from some file, database, or communication from other processes — the pickle module is a good example of needing such advanced approaches). I don’t think you should worry about them at all at this stage of your Python learning experience.