類的實現

class People():
    def __init__ (self, name, sex, ID):
        self.name = name
        self.sex = sex
        self.ID = ID
        
    def print_data(self):
        print 'the person is %s %s %s' %(self.name, self.sex, self.ID)
        
P1 = People('Ivy', 'girl', 111)
#P1.print_data()
print P1.name      #猜到內容你能夠修改哦

爲了使用戶不能猜到name等關鍵字,__加入可讓外部沒法訪問

class People():
    def __init__ (self, name, sex, ID):
        self.__name = name
        self.__sex = sex
        self.__ID = ID
        
    def print_data(self):
        print 'the person is %s %s %s' %(self.__name, self.__sex, self.__ID)
        
P1 = People('Ivy', 'girl', 111)
#P1.print_data()
print P1.__name   #沒有辦法啦，私有的函數不能訪問

2)如何修改外部沒法訪問的參數？主要做用是對其添加的進行判斷

class People():
    def __init__ (self, name, sex, ID):
        self.__name = name
        self.__sex = sex
        self.__ID = ID
        
    def print_data(self):
        print 'the person is %s %s %s' %(self.__name, self.__sex, self.__ID)
    
    def get_ID(self, reID):
        self.__ID = reID
        if reID > 150:
            print 'large number'
        else:
            print 'small number'                    
       
P1 = People('Ivy', 'girl', '111')
P1.get_ID(123)
P1.print_data()