Chapter 8: Classes, Objects & Methods

example 8.1, page no. 132

class Rectangle:
    length = 0
    width = 0
    def getData(self, x, y):
        self.length = x
        self.width = y
    def rectArea(self):
        area = self.length * self.width
        return area

rect1 = Rectangle()
rect1.length = 15
rect1.width = 10
rect2 = Rectangle()
area1 = rect1.length*rect1.width
rect2.getData(20,12)
area2 = rect2.rectArea()
print "Area1 = ", area1
print "Area2 = ", area2

 Area1 =  150
Area2 =  240

example 8.2, page no. 134

class Rectangle:
    length = 0
    width = 0
    def __init__(self, x=0, y=0):
        self.length = x
        self.width = y
    def rectArea(self):
        return self.length * self.width
rect1 = Rectangle(15, 10)
area1 = rect1.rectArea()
print "Area1 = ", area1

Area1 =  150

example 8.3, page no. 136

#there are no static methods in Python, we will use normal methods instead

class MathOperations:
    def mul(self, x, y):
        return x*y
    def divide(self, x, y):
        return x/y

obj = MathOperations()
a = obj.mul(4.0,5.0)
b = obj.divide(a,2.0)
print "b = ", b

b =  10.0

example 8.3, page no. 137

class Nesting:
    m = 0
    n = 0
    def __init__(self, x, y):
        self.m = x
        self.n = y
    def largest(self):
        if(self.m>=self.n):
            return self.m
        else:
            return self.n
    def display(self):
        large = self.largest()
        print "Largest Value: ", large

nest = Nesting(50, 40)
nest.display()

Largest Value:  50

example 8.4, page no. 139

class Room(object):
    def __init__(self, x, y):
        self.length = x
        self.breadth = y
    def area(self):
        return self.length*self.breadth

class BedRoom(Room):
    height = 0
    def __init__(self, x, y, z):
        Room.__init__(self, x, y)
        self.height = z
    def volume(self):
        return self.length*self.breadth*self.height

room1 = BedRoom(14, 12, 10)
area1 = room1.area()
volume1 = room1.volume()
print "Area = ", area1
print "Volume = ", volume1

Area =  168
Volume =  1680

example 8.6, page no. 142

class Super(object):
    x = 0
    def __init__(self, x):
        self.x = x
    def display(self):
        print "Super x = ", self.x

class Sub(Super):
    y = 0
    def __init__(self, x, y):
        Super.__init__(self, x)
        self.y = y
    def display(self):
        print "Super x = ", self.x
        print "Sub y = ", self.y
s1 = Sub(100, 200)
s1.display()

Super x =  100
Sub y =  200

example 8.7, page no. 145

class Exampleprg:
    def __init__(self, *args):
        for arg in args:
            print "Hello ", arg

e = Exampleprg("John", "David", "Suhel")

Hello  John
Hello  David
Hello  Suhel