Magic methods

Small list

Magic methods are special methods that can be implemented, and then be used with standard Python constructions like +, len(..), print(...), etc.

Python constructions	Real thing happening with magic methods
`1+2`	`(1).__add__(2)`
`2 * 3`	`(2).__mul__(3)`
len(a)	`a.__len__()`
print(a)	`print(a.__repr__)`

Full list here: https://docs.python.org/3/reference/datamodel.html#specialnames

Example

from dataclasses import dataclass

@dataclass
class Vector2D:
    """Class for representing a point in 2D."""
    x: float
    y: float

    def __add__(self, other):
        return Vector2D(self.x + other.x, self.y + other.y)

print(Vector2D(2, 3) + Vector2D(10, 40))

Vector2D(x=12, y=43)

There are libraries to manipulate numbers with units, e.g. https://pypi.org/project/Pint/