"Python self-taught" Chapter XII programming paradigm

Object-Oriented Programming

Class class

class Orange:
    def __init__(self,w,c):
        self.weight = w
        self.color = c
        print("Created!")
orl = Orange(10,"dark orange")
print(orl.color)
print(orl.weight)

class Orange:
    def __init__(self,w,c):
        self.weight = w
        self.color = c
        print("Created!")
orl = Orange(10,"dark orange")
orl = Orange(8,"light orange")
orl = Orange(6,"yellow orange")
>>> 
Created!
Created!
Created!

Oranges will rot

class Orange():
    def __init__(self,w,c):
        self.weight = w
        self.color = c
        self.mold = 0
        print("Created!")


    def rot(self,days,temp):
        self.mold = days * temp

orange = Orange(6,"yellow")
print(orange.mold)
orange.rot(10,98)
print(orange.mold)

Calculation area of ​​a rectangle

class Rectangle():
    def __init__(self,w,l):
        self.width = w
        self.len = l


    def area(self):
        return self.width * self.len

    def change_size(self,w,l):
        self.width = w
        self.len = l

rectangle = Rectangle(10,20)
print(rectangle.area())
rectangle.change_size(20,40)
print(rectangle.area())

Exercise Challenge

1. The definition of a class called Apple to create four instance variables that Apple's four kinds of attributes.

class Apple():
    def __init__(self,w,v,c,f):
        self.weight = w
        self.volume = v
        self.color = c
        self.feel = f

apple = Apple(8,2,"red","good")
print(apple.weight)
print(apple.volume)
print(apple.color)
print(apple.feel)

2. The definition of a class called Circle, create area method to calculate its area. Then create a Circle
object, call its area method, print the results. Python using the built-in module pi math functions.

import math


class Circle():
    def __init__(self,r):
        self.round = r

    def area(self):
        return math.pi * r * r

r = int(input("请输入半径："))
circle = Circle(r)
print(circle.area())

3. The definition of a class called Triangle, create a method to calculate area and returns the area. Then create a
Triangle object, call its area method, print the results.

class Triangle():
    def __init__(self,w,l):
        self.width = w
        self.length = l

    def area(self):
        return w * l

w = int(input("请输入宽度："))
l = int(input("请输入长度："))
triangle = Triangle(w,l)
print(triangle.area())

4. Hexagon define a called class methods create cacculate_perimeter, computes and returns
its circumference. Then create a Hexagon object, call its calculate_perimeter method, and hit
print results.

class Hexagon():
    def __init__(self,w,l):
        self.width = w
        self.length = l

    def calculate_perimeter(self):
        return (self.width + self.length ) * 2

hexagon = Hexagon(20,30)
print(hexagon.calculate_perimeter())