How can I unpack two values from user defined class?

Question

class Vector:
    def __init__(x,y):
        self.x=x
        self.y=y

How can I get two variables x,y=Vector(20,10)?

Answer should be x=20, y=10.

Answer 1

If you just want to access the x and y attribute, you can access them using the dot notation:

class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y
vector = Vector(10, 20)
x = vector.x
y = vector.y

print('x =', x)
print('y =', y)

# Output
x = 10
y = 20

If you want to give your class a behavior similar to tuple unpacking, you can override __iter__:

class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __iter__(self):
       yield self.x
       yield self.y

    def __str__(self):
        return 'x={}, y={}'.format(self.x, self.y)

vector = Vector(x=10, y=20)
print(vector)

x, y = vector
print('x =', x)
print('y =', y)

# Output
x=10, y=20
x = 10
y = 20

Answer 2

Your __init__ method is currently defined incorrectly; the signature should be def __init__(self, x, y), where the important thing to note is that the first parameter is self.

Without defining some method to return the x and y values as a tuple, you wouldn't be able to extract them as x, y = Vector(10, 20), you would need to access the instance attributes separately, i.e.:

vector = Vector(10, 20)
x = vector.x
y = vector.y

Alternatively, you could define an extra method on the class to return a tuple and unpack that:

class Vector:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def coords(self):
        return self.x, self.y

vector = Vector(10, 20)
x, y = vector.coords()
print(x, y)

Output:

10 20