知识点：类

 1 class Person:
 2     def __init__(self, name):  #self是每个方法的默认参数，不需要设定，所有输入参数都是从第二个开始设置
 3         self.name = name
 4     def sayHi(self):
 5         print(‘Hello, my name is ‘ + self.name)
 6          
 7  
 8 p = Person(‘marian‘)   #第一个参数self是默认参数，‘marian‘的设定是对name的赋值
 9 p.sayHi()
 
 >>> Hello, my name is marian

class DerivedClassName(baseClassName): #baseClassName:基类，父类或超类
    ....

import random as r

class Fish:
    def __init__(self): #类的构造方法
        self.x = r.randint(0 , 10)
        self.y = r.randint(0 , 10)

    def move(self):
        self.x -=1
        print("我是位置是",self.x,self.y)

class Shark(Fish):        #继承父类
    def __init__(self):   #重写父类方法
        print("我要吃了你！")

fish = Fish()
fish.move()
>>> 我是位置是 5 9

import random as r

class Fish:
    def __init__(self):
        self.x = r.randint(0 , 10)
        self.y = r.randint(0 , 10)

    def move(self):
        self.x -=1
        print("我是位置是",self.x,self.y)

class Shark(Fish):
    def __init__(self):
        super().__init__()  #如果要修改父类的方法，可以先继承父类中方法的内容。加入此句，可以解决下面的错误
        print("我要吃了你！")

shark = Shark()
shark.move()

###################################
#Traceback (most recent call last):
#  File "C:/Python33/test.py", line 17, in <module>
#    shark.move()
#  File "C:/Python33/test.py", line 9, in move
#    self.x -=1
#AttributeError: ‘Shark‘ object has no attribute ‘x‘
######################################

>>>我要吃了你！
>>>我是位置是 7 0

class DerivedClassName(Base1 , Base2 , Base 3): 
    ....

class Base1:
def foo1(self):
print("我是foo1,我为Base1代言！")

class Base2:
def foo2(self):
print("我是foo2,我为Base2代言！")

class C(Base1 , Base2):
pass


c = C()
c.foo1()
c.foo2()


>>>我是foo1,我为Base1代言！
>>>我是foo2,我为Base2代言！

 1 class Bird:
 2     def fly(self):
 3         print("fly away!")
 4 
 5 class Penguin(Bird):
 6     def fly(self):
 7         pass
 8 
 9 bird = Bird()
10 penguin = Penguin()
11 
12 bird.fly()
13 penguin.fly() 

 >>> fly away!

class Turtle:
    def __init__(self , x):
        self.num = x

class Fish:
    def __init__(self , x):
        self.num = x

class Pool:
    def __init__(self , x , y):
        self.turtle = Turtle(x)
        self.fish = Fish(y)

    def printNum(self):
        print("水池里面有%d之乌龟和%d只鱼" % (self.turtle.num , self.fish.num))


pool = Pool(10,20)
pool.printNum()
>>>水池里面有10之乌龟和20只鱼