从0开始的Python学习014面向对象编程

class 类名():
    代码块

‘‘‘the first class
    from liu
    我们使用class语句后跟类名，创建了一个新的类。这后面跟着一个缩进的语句块形成类体。在这个例子中，我们使用了一个空白块，它由pass语句表示。

接下来，我们使用类名后跟一对圆括号来创建一个对象/实例。（我们将在下面的章节中学习更多的如何创建实例的方法）。为了验证，我们简单地打印了这个变量的类型。它告诉我们我们已经在__main__模块中有了一个Person类的实例。

可以注意到存储对象的计算机内存地址也打印了出来。这个地址在你的计算机上会是另外一个值，因为Python可以在任何空位存储对象。
    ‘‘‘
class Person:
    pass # 空块 

p = Person()
print (p)
print(__doc__)

class Person:
    def sayHi(self):
        print(‘Hello,how are you?‘)

p = Person()
p.sayHi()

‘‘‘__init__方法
    __init__一个对象被建立的时候，马上运行。这个方法是对你的对象的初始化。
    这个名称的开始和结尾都是双下划线。‘‘‘

class Person:
    def __init__(self,name):
        self.name = name

    def sayHi(self):
        print(‘Hello,my name is ‘,self.name)

p = Person(‘happyLiu‘)
p.sayHi()

class Person:
    def __init__(self,name):
        print(‘这是初始化块‘)
        self.name = name

    def sayHi(self):
        print(‘Hello,my name is ‘,self.name)

p = Person(‘happyLiu‘)
p.sayHi()

class Person:
    population = 0

    def __init__(self,name):
        self.name = name
        print(‘Initalizing %s‘ % self.name)

        Person.population += 1

    def __del__(self):
        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):
        print(‘Hi, my name is %s.‘ % self.name)

    def howMany(self):
        if Person.population == 1:
            print(‘I am the only person here.‘)
        else:
            print(‘We have %d persons here.‘ % Person.population)

happy = Person(‘happyLiu‘)
happy.sayHi()
happy.howMany()

bob = Person(‘bob james‘)
bob.sayHi()
bob.howMany()

del bob

happy.sayHi()
happy.howMany()

class 子类(父类):
    代码块

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:%d‘%(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)

class Student(SchoolMember):
    ‘‘‘Represents a student.‘‘‘
    def __init__(self, name, age, marks):
        SchoolMember.__init__(self,name,age)
        self.marks = marks
        print(‘(Initialized Student: %s)‘ % self.name)
        
    def tell(self):
        SchoolMember.tell(self)
        print(‘Marks: "%d"‘%self.marks)

t = Teacher(‘Mr,Liu‘,25,3000)
s = Student(‘Swaroop‘, 22, 75)

print()

members = [t,s]
for member in members:
    member.tell()