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python之7-1类

  • 面向对象的编程,其实是将对象抽象成类,然后在类中,通过init定义实例初始化函数和多个操作实例的函数.

  • 整个类就如同一个模板,我们可以用这个模板生成众多具现实例,并赋予实例动作.

  • py中定义类的大致格式如下:

class 类名():类变量名 =类名.类变量名    #调用类变量    def _init_(self,参数1,参数2):   #这里的参数也可以没有,即可以直接 self.属性 = 值  而self每次对应的就是实例自己        self.属性1 = 参数1        self.属性2 = 参数2    def 实例方法函数名(self,方法变量1,方法变量2):           函数体实例名 = 类名(参数1,参数2)    #实例创建实例名.实例方法函数名()    #实例动作函数调用
  • 注释1:self这里就是实例统称,属性1和属性2是类的属性,然后将属性1和属性2获得的参数传递给实例,构建实例的属性,最后这些实例属性,被方法函数所调用

  • 注释2:

类 就像是 包;

init函数 就如同包里面的 init模块 ,来介绍这个类;

方法函数 就像是包里面的 其他模块,来具体实现类的操作

  • 例子1:
#!/usr/bin/python# Filename: objvar.pyclass Person:    ‘‘‘Represents a person.‘‘‘    population = 0    def __init__(self, name):        ‘‘‘Initializes the person‘s data.‘‘‘        self.name = name        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.populationswaroop = Person(‘Swaroop‘)swaroop.sayHi()swaroop.howMany()kalam = Person(‘Abdul Kalam‘)kalam.sayHi()kalam.howMany()swaroop.sayHi()swaroop.howMany()
  • 例子2:获取一组连续数字的中间数字
#!/usr/bin/python2.6class lis:    def __init__(self, start, end):        self.start = start        self.end = end    def test(self):        if ( self.start % 2 == 0 and self.end % 2 == 0 ) or ( self.start % 2 == 1 and self.end % 2 == 1):            print ( self.start + self.end ) / 2        elif self.start % 2 == 1 or self.end % 2 == 1:            tmp_num = ( self.start + self.end + 1) / 2            print tmp_num - 1, tmp_numa = lis(1,10)b = lis(1,9)c = lis(2,10)d = lis(2,9)a.test()b.test()c.test()d.test()