Operator overloading

12.2. Operator overloading#

12.2.1. Basic Class#

import math
class Circle:

    def __init__(self, radius):
        self.radius = radius

    def get_area(self):
        return math.pi * self.radius**2


    def __repr__(self):
        return "Circle with radius " + str(self.radius)
    def __str__(self):
        return "Circle with radius " + str(self.radius)

c1 = Circle(10)
c2 = Circle(5)

print(c1)
print(c2)
print(c2.get_area())

Circle with radius 10
Circle with radius 5
78.53981633974483

12.2.2. Adding Add#

class Circle:

    def __init__(self, radius):
        self.radius = radius

    def get_area(self):
        return math.pi * self.radius**2

    def __str__(self):
        return "Circle with radius " + str(self.radius)

    def __add__(self, another_circle):
        return Circle(self.radius + another_circle.radius)


c1 = Circle(10)
c2 = Circle(5)
c3 = c1 + c2 ### ==> c1.__add__(c2) ==> Circle.__add__(c1, c2)
print(c3)

Circle with radius 15

class Circle:

    def __init__(self, radius):
        self.radius = radius

    def get_area(self):
        return math.pi * self.radius**2

    def __str__(self):
        return "Circle with radius " + str(self.radius)

    def __add__(self, another_circle):
        return Circle(self.radius + another_circle.radius)

    def __gt__(self, another_circle):
        return self.radius > another_circle.radius

    def __lt__(self, another_circle):
        return self.radius < another_circle.radius



c1 = Circle(10)
c2 = Circle(5)
print(c1 < c2)

False

class Point:
    def __init__(self, x=0, y=0):
        self.x = x
        self.y = y

    def __add__(self, another_point):
        return Point(self.x + another_point.x, self.y + another_point.y)

    def __sub__(self, another_point):
        return Point(self.x - another_point.x, self.y - another_point.y)

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

p1 = Point(3, 4)
p2 = Point(8, 6)
print(p2+p1)

11, 10

import math
class Point:
    def __init__(self, x=0, y=0):
        self.x = x
        self.y = y

    def __add__(self, another_point):
        return Point(self.x + another_point.x, self.y + another_point.y)

    def __sub__(self, another_point):
        return Point(self.x - another_point.x, self.y - another_point.y)

    def length(self):
        return math.sqrt(self.x**2 + self.y**2)

    def distance(self, another_point):
        return (self - another_point).length()

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

p1 = Point(3, 4)
p2 = Point(8, 6)
print(p1.distance(p2))

5.385164807134504

12.2.3. Iterator Class#

Three Requirements:

  1. iter() initializes the iterator class. Its purpose is to reset the state of the iterator, which means resetting the value.

  2. next() requires you to save the current value, increment it, and then return or emit it.

  3. Raise `StopIteration`` when you have exhausted your values.

class MyRange:

    def __init__(self, limit):
        self.limit = limit

    def __iter__(self):
        self.value = 0
        return self

    def __next__(self):
        if self.value < self.limit:
            output = self.value
            self.value += 1
            return output
        else:
            raise StopIteration


i = iter(MyRange(10))
next(i)
for ele in MyRange(10):
    print(ele)


class PowX:
    def __init__(self, limit, power):
        self.limit = limit
        self.power = power

    def __iter__(self):
        self.value = 0
        return self

    def __next__(self):
        if self.value < self.limit:
            output = self.value**self.power
            self.value += 1
            return output
        else:
            raise StopIteration


for ele in PowX(10, 3):
    print(ele)


## lets use generator

def PowX(limit, power):
    value = 0
    while value < limit:
        yield value**power
        value += 1

for ele in PowX(10, 3):
    print(ele)

new_list = []
for number in numbers:

    if number % 2 == 0
        new_list.append(number)
        I am here!!

  Cell In[6], line 61
    if number % 2 == 0
                      ^
SyntaxError: expected ':'
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