Help !! Magic Methods (dunders)

Question

help me understand the logic of this code :
( I mean what is happening in the program )

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

first = Vector2D(5, 7)
second = Vector2D(3, 9)
result = first + second
print(result.x)
print(result.y)

Answer 1

Magic methods allow you to define how operators like + work for your classes. In this case, the program defines a class named Vector2D, a method for initializing it (__init__), and a method for adding one Vector2D with another (__add__). Then it creates two instances of the class and adds them together to show you how it works.

Answer 2

my problem is that:
1. when we call Vector2D for the second time, what will happen to the first one ?? does the program store it somewhere ???
and
2. where we defined that + in this line
result = first + second
would give us the sum of the elements ??
3.why we cannot do it with the regular methods ??
4.why in this line
def __add__(self, other):
other is operating just like self but in __init__ the other values will use as unknowns !!

Answer 3

Simply, writing
a + b
is exactly the same as
a.__add__(b)
or, if not defined,
b.__radd__(a)