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Python Program to Find the Area of a Rectangle Using a Class

Beginner · Classes and objects

This program defines a Rectangle class that stores a length and a breadth, with methods that work out the area and the perimeter. The area of a rectangle is length x breadth, and the perimeter is 2 x (length + breadth).

Program

rectangle_class.py
class Rectangle:
def __init__(self, length, breadth):
self.length = length
self.breadth = breadth
def area(self):
return self.length * self.breadth
def perimeter(self):
return 2 * (self.length + self.breadth)
def is_square(self):
return self.length == self.breadth
r1 = Rectangle(8, 5) # or: r1 = Rectangle(float(input("Length: ")), float(input("Breadth: ")))
r2 = Rectangle(6, 6)
for r in [r1, r2]:
print(f"Rectangle {r.length} x {r.breadth}")
print(" Area:", r.area())
print(" Perimeter:", r.perimeter())
print(" Is it a square?", r.is_square())
Output
Rectangle 8 x 5
  Area: 40
  Perimeter: 26
  Is it a square? False
Rectangle 6 x 6
  Area: 36
  Perimeter: 24
  Is it a square? True

How it works

  1. __init__ stores the length and breadth inside each new object as self.length and self.breadth.
  2. area() and perimeter() use those stored values, so they are called with no arguments: self is passed automatically.
  3. is_square() returns True when both sides are equal, as they are for the 6 x 6 rectangle.
  4. The two objects come from one class but keep their own measurements, so one loop can report on both.

Another way to write it

Comparing rooms stored as objects

Comparing rooms stored as objects
class Rectangle:
def __init__(self, length, breadth):
self.length = length
self.breadth = breadth
def area(self):
return self.length * self.breadth
rooms = {"Bedroom": Rectangle(4, 3.5), "Kitchen": Rectangle(3, 2.5), "Hall": Rectangle(6, 4.5)}
for name, room in rooms.items():
print(f"{name}: {room.area()} square metres")
biggest = max(rooms, key=lambda name: rooms[name].area())
print("The biggest room is the", biggest)
Output
Bedroom: 14.0 square metres
Kitchen: 7.5 square metres
Hall: 27.0 square metres
The biggest room is the Hall

Objects can be stored in a dictionary like any other value, and max() with a key function picks the room whose area is largest.

Try it yourself

Add a diagonal() method that returns (self.length ** 2 + self.breadth ** 2) ** 0.5.

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