Python支持面向对象的特性，即类、继承、多态等，现在只简单看下类和继承的定义和使用 1. 类和对象 Python中用class关键字声明一个类，类体在缩进块中进行定义。类中有一个self成员，相当于C++中的this 2. 构造函数和析构函数 构造函数__init__，析构函数__del__。构造函数和析构函数可以有参数。 3. 类的变量 类的变量可以属于对象，也可以属于类（相当于C++中的静态变量） class Person: '''Represents a person.''' population = 0 # population属于整个类 def __init__(self, name): '''Initializes the person's data.''' self.name = name # name属于对象 print('(Initializing %s)' % self.name) # When this person is created, he/she # adds to the population Person.population += 1 def __del__(self): '''I am dying.''' print('%s says bye.' % self.name) Person.population -= 1 if Person.population == 0: print('I am the last one.') else: print('There are still %d people left.' % Person.population) def sayHi(self): '''Greeting by the person. Really, that's all it does.''' print('Hi, my name is %s.' % self.name) def howMany(self): '''Prints the current population.''' if Person.population == 1: print('I am the only person here.') else: print('We have %d persons here.' % Person.population) 4. 继承 Python支持单继承和多继承。 class SchoolMember: '''Represents any school member.''' def __init__(self, name, age): self.name = name self.age = age print('(Initialized SchoolMember: %s)' % self.name) def tell(self): '''Tell my details.''' print('Name:"%s" Age:"%s"' % (self.name, self.age)) class Teacher(SchoolMember): '''Represents a teacher.''' def __init__(self, name, age, salary): SchoolMember.__init__(self, name, age) self.salary = salary print('(Initialized Teacher: %s)' % self.name) def tell(self): SchoolMember.tell(self) print('Salary: "%d"' % self.salary)
