python类和对象.doc

一、 类和对象的概念对象=属性+行为（方法）把具有相同属性和方法的对象归为一类。类是对象的抽象化，对象是类的实例化。二、 类的定义、实例化、属性和方法的调用class 类名： 属性方法 class people:name=jimage=20def printName(self):print jim people.pTraceback (most recent call last): File , line 1, in people.pAttributeError: class people has no attribute p people.printName()Traceback (most recent call last): File , line 1, in people.printName()TypeError: unbound method printName() must be called with people instance as first argument (got nothing instead) people.printName(self)Traceback (most recent call last): File , line 1, in people.printName(self)NameError: name self is not defined p=people() jim p.age20 p.printName()jim class people1:_name=mike_age=20sex=wemom p1=people1() p1._nameTraceback (most recent call last): File , line 1, in p1._nameAttributeError: people1 instance has no attribute _name p1._ageTraceback (most recent call last): File , line 1, in p1._ageAttributeError: people1 instance has no attribute _age p1.sexwemom p1.sexwemom类的内置函数class c1:def tell(self):print this is a classdef _init_(self):print c1 is initdef _del_(self):print c1 is del c11=c1()c1 is init c11=0c1 is del三、 类属性、实例属性、类方法、实例方法、静态方法 class people:name=alice_age=13 p=people() alice p._ageTraceback (most recent call last): File , line 1, in p._ageAttributeError: people instance has no attribute _age实例对象可以调用类里面定义的公有属性，不能调用私有属性。 alice people._ageTraceback (most recent call last): File , line 1, in people._ageAttributeError: class people has no attribute _age类对象可以调用类里面定义的公有属性，不能调用私有属性。 p.sex=man #sex是实例属性 people.sexTraceback (most recent call last): File , line 1, in people.sexAttributeError: class people has no attribute sex 实例属性不能被类对象调用 p2=people() p2.sexTraceback (most recent call last): File , line 1, in p2.sexAttributeError: people instance has no attribute sex实例属性不能被其他实例对象调用 p.sexman实例属性只能被定义该属性的实例对象调用 class people:country=chinaclassmethod #声明为类方法def getCountry(cls):return cls.country people.getCountry()china类方法可以被类对象调用 p=people() p.getCountry()china类方法可以被实例对象调用 class people:country=chinaclassmethoddef getCountry(cls):return cls.countryclassmethoddef setCountry(cls,a): #使用类方法修改类属性cls.country=a return a p=people() p.getCountry()china p=people() p=people() p.setCountry(a)a people.setCountry(b)b class people:country=chinadef getCountry(self): #实例属性return self.country people.getCountry()Traceback (most recent call last): File , line 1, in people.getCountry()TypeError: unbound method getCountry() must be called with people instance as first argument (got nothing instead)实例方法不能被类对象访问 p=people() p.getCountry()china实例方法可以被实例对象访问 class people:country=chinastaticmethod #声明为静态方法，静态方法不需要参数def getCountry():return people.country print people.getCountry()China静态方法可以被类对象访问p=people() p.getCountry()china静态方法也可以被实例对象访问四、 继承单继承：class student: name=aa age=13 def _init_(self): =bb self.grade=high self._sex=man print initing def _del(self): print dead def eat(self): print i am eating staticmethod def runSelf(): print in static method def _hello(self): print helloclass miniStudent(student): passmini=miniStudent()print mini._hello()多继承：class studentA: def _init_(self): print init studentA def smile(self): print smileclass student: name=aa age=12 def _init_(self): self.addr=