#面向对象:多态、封装、继承#1 多态：意味着即使不知道变量所引用的对象类型是什么，还是能对他进行操作，而且也会根据他的不同类型表现出不同的行为#多态和方法

from random import choicex = choice(['Hello World',['1','1','1','2','3']])print(x)print(x.count('1'))#1出现的次数 不需要检测类型 只需要知道有conut这个方法#多态的多种形式：+运算对字符串、数字起作用

#2 封装对全局作用域中的其他区域隐藏多余信息#3 继承：不想代码重复 使用原来的代码#4 类#创建类_metaclass_= typeclass Person:def setname(self,name):self.name = namedef getname(self):return self.namedef greet(self):print("Hello I am %s"%self.name)#调用类foo = Person()bar = Person()foo.setname("1234567")bar.setname("7891213")foo.greet()bar.greet()print(foo.name,bar.name)#-------------------------输出结果----------------------------------#"""C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.pyHello World0Hello I am 1234567Hello I am 78912131234567 7891213"""

#特性、函数、方法class Class:def method(self):print("I am self")def fuction():print("I don't...")

obj = Class()obj.method()obj.method = fuction # 特性绑定到一个普通的函数上obj.method()

test = obj.method #test变量引用绑定方法上test()

#-------------------------输出结果----------------------------------#"""I am selfI don't...I don't.."""

#私有特性：为了让特性和方法变成私有（外部不能访问），只要在名字前加上双下划线#指定超类class Filter:def init(self):self.blocked=[]def filter(self,test):return [x for x in test if x not in self.blocked]def _test(self):print("我是私有的")class ChildFilter(Filter):#指定超类 ChildFilter为Filter的子类 def init(self):print("我是子类 正在重写父类方法")self.blocked=['as']f = Filter()f.init()print(f.filter([1,2,3]))

f1 = ChildFilter()f1.init()print(f1.filter([1,23,56]))

#-------------------------输出结果----------------------------------#"""C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.py[1, 2, 3]我是子类 正在重写父类方法[1, 23, 56]"""

#捕获异常try: x = 5 y = 0 print(x/y)except ZeroDivisionError:print("分母不能为0")#-------------------------输出结果----------------------------------#"""C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.py分母不能为0"""

# raiseclass MuffledCalculator: muffed = False def calc(self,expr):try:return eval(expr)except ZeroDivisionError:if self.muffed:print("Division is zero by illegal")else:raise #cal = MuffledCalculator()print(cal.calc('10/2'))cal.muffed = True #打开屏蔽机制print("hehehe-->",cal.calc('10/0'))#-------------------------输出结果----------------------------------#"""C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.py分母不能为05.0Division is zero by illegalhehehe--> None"""

#用一个块捕捉两个异常try: x = input("input your first num:") y = input("input your second num:")print(x/y)except(ZeroDivisionError,TypeError,NameError).e:print("Your Num were bug")print(e)

while True:try: x = int(input("input your first num:")) y= int(input("input your second num:")) value = x/yprint(value)except Exception.e:print("Exception ",e)print("try again")else:break

"""#-------------------------输出结果----------------------------------#C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.pyinput your first num:10input your second num:33.3333333333333335C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.pyinput your first num:10input your second num:0Traceback (most recent call last): File "D:/Python-Test/qiubai/qiubai/Test6.py", line 145, in <module> value = x/yZeroDivisionError: division by zeroDuring handling of the above exception, another exception occurred:Traceback (most recent call last): File "D:/Python-Test/qiubai/qiubai/Test6.py", line 147, in <module> except Exception.e:AttributeError: type object 'Exception' has no attribute 'e'"""while True: try: x = int(input("input your first num:")) y= int(input("input your second num:")) value = x/y print(value) except: print("try again") else:#只有程序没有异常情况才会退出 只要错误发生，程序会不断重新要求输入 break"""#-------------------------输出结果----------------------------------#C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.pyinput your first num:10input your second num:0try againinput your first num:10input your second num:33.3333333333333335"""#Finally:x = Nonetry: x = x / 0finally:#通常用于关闭文件或网络套接字 print('Clean up .....') del x #程序崩溃之前 对于x的变量清理 """C:\python3.7\python.exe D:/Python-Test/qiubai/qiubai/Test6.pyClean up .....Traceback (most recent call last): File "D:/Python-Test/qiubai/qiubai/Test6.py", line 203, in <module> x = x / 0TypeError: unsupported operand type(s) for /: 'NoneType' and 'int'"""