Python类的基本使用方法有哪些

class ClassName:....    ....    ....

class Fruit:#这是类的一个基本属性self.number = 100def get_number(self):                a = self.number + 100return af = Fruit()print('We have {0} fruits'.format(f.number))print('We have {0} fruits'.format(f.get_number()))

We have 100 fruitsWe have 200 fruits

def __init__(self):self.data = []

class Fruit:def __init__(self):                print('你已经实例化了一个对象')f = Fruit()

你已经实例化了一个对象

class Complex:def __init__(self,real,image):self.r = realself.i = imagedef get_complex(self):                print('complex real is %.2f , image is %.2f'%(self.r,self.i))a = Complex(3.5,-3)a.get_complex()

complex real is 3.50 , image is -3.00

class Test:def prt(self):        print(self)        print(self.__class__)t = Test()t.prt()

<__main__.Test object at 0x0000025EC6D45608><class '__main__.Test'>

class Complex:def __init__(self, real=None, image=None):self.r = realself.i = imagedef get_complex(self):        print('complex real is %.2f , image is %.2f' % (self.r, self.i))    @staticmethoddef test(a, b):        print('complex real is %.2f , image is %.2f' % (a, b))a = Complex(3.5, -3)a.get_complex()b = Complex()b.test(3, -2)

complex real is 3.50 , image is -3.00complex real is 3.00 , image is -3.00

class Derivedclassname(Baseclassname):    ...    ...

class Fruit:    def __init__(self,sweet):        self.sweetness = sweet    def describe(self):        print('Our fruit has a sweetness of %.2f'%self.sweetness)class Apple(Fruit):#单继承，继承fruit类    def __init__(self,sweet,color):        self.color = color        Fruit.__init__(self,sweet)    def describe(self):#改写基类fruit的方法        print('Our apple has a sweetness of {0:.2f}%,and color is {1}'.format(self.sweetness,self.color))apple = Apple(62.2,'red')apple.describe()

Our apple has a sweetness of 62.20%,and color is red

class Derivedclassname(basename1,basename2,...):    ...    ...    ...

class Fruit:def __init__(self, sweet):        self.sweetness = sweetdef describe(self):        print('Our fruit has a sweetness of %.2f' % self.sweetness)class Food:def __init__(self, uprice, num):        self.unit_price = uprice        self.number = num        self.total_price = num * upricedef cost(self):        print('You need to pay {0:.3} yuan, thank you'.format(self.total_price))class Apple(Fruit, Food):def __init__(self, sweet, color, uprice, num):        self.color = color        Fruit.__init__(self, sweet)        Food.__init__(self, uprice, num)def describe(self):        print('Our fruit has a sweetness of {0:.2f}%,and color is {1}'.format(self.sweetness, self.color))

apple = Apple(62.2,'red',3.5,21)apple.describe()apple.cost()

Our fruit has a sweetness of 62.20%,and color is redYou need to pay 73.5 yuan, thank you

class Parent_class:def Method(self):         print ('父类方法')class Child_class(Parent_class): # 定义子类def Method(self):        print ('子类方法')c = Child_class()                # 子类实例化c.Method()                  # 子类调用重写方法super(Child_class,c).Method()    #用子类对象调用父类已被覆盖的方法

class A:def __init__(self, x, y):        self.x = x        self.y = y        print('pos is ({0},{1})'.format(self.x, self.y))def xxx(self):        print('parent now')class B(A):def xxx(self):        print('child now')b = B(10, 3)b.xxx()

pos is (10,3)child now

class JustCounter:     __secretCount = 0  # 私有变量    publicCount = 0  # 公开变量def count(self):        self.__secretCount += 1        self.publicCount += 1       print(self.__secretCount)counter = JustCounter()counter.count()counter.count()print(counter.publicCount)print(counter.__secretCount)  # 报错，实例不能访问私有变量

Traceback (most recent call last):File "test.py", line 16, in <module>    print (counter.__secretCount)  # 报错，实例不能访问私有变量AttributeError: 'JustCounter' object has no attribute '__secretCount'

class Site:def __init__(self, name, url):        self.name = name  # public        self.__url = url  # privatedef who(self):        print('name  : ', self.name)        print('url : ', self.__url)def __foo(self):  # 私有方法        print('这是私有方法')def foo(self):  # 公共方法        print('这是公共方法')        self.__foo()x = Site('***', 'www.xxx.com')x.who() # 正常输出x.foo() # 正常输出x.__foo()  # 报错

'''name  :  ***url :  www.***.com这是公共方法这是私有方法Traceback (most recent call last):  File "F:PythonProgram	est.py", line 61, in <module>    x.__foo()      # 报错AttributeError: 'Site' object has no attribute '__foo''''

class Name:def __init__(self, name):        self.name = nameprint(Name('s'))

'''<__main__.Name object at 0x0000023744AFD248>'''

class Name:def __init__(self,name):        self.name = namedef __repr__(self): #控制了在打印类时候的输出          return 'Name({!r})'.format(self.name)print(Name('s'))'''Name('s')'''

class CountList:def __init__(self, *args):        self.list = [x for x in args]        self.count = self.__len__()def __len__(self):         return len(self.list)def get_count(self):         return self.counta = CountList(1, 2, 3, 4, 4, 5)print(a.get_count())print(len(a))

class MyClass:def __init__(self, height, weight):        self.height = height        self.weight = weight# 两个对象的长相加，宽不变.返回一个新的类def __add__(self, others):        return MyClass(self.height + others.height, self.weight + others.weight)# 两个对象的宽相减，长不变.返回一个新的类def __sub__(self, others):        return MyClass(self.height - others.height, self.weight - others.weight)# 说一下自己的参数def intro(self):        print("高为", self.height, " 重为", self.weight)def main():    a = MyClass(height=10, weight=5)    a.intro()    b = MyClass(height=20, weight=10)    b.intro()    c = b - a    c.intro()    d = a + b    d.intro()if __name__ == '__main__':    main()

'''高为 10  重为 5高为 20  重为 10高为 10  重为 5高为 30  重为 15'''