#coding:utf-8

class Student(object):
    # 双下划线开头,并且以双下划线结尾的,是特殊变量
    def __init__(self,name,score):
        # 私有变量(private)
        self.__name = name
        self.__score = score

    # 外部代码获取name和score
    def get_name(self):
        return self.__name

    def get_score(self):
        return self.__score

    def print_score(self):
        print('%s : %d - %s' %(self.__name,self.__score,self.get_grade()))

    # 外部代码修改name和score
    def set_name(self,name):
        self.__name = name

    def set_score(self,score):
        self.__score = score

    # 判断成绩 
    def get_grade(self):
        if self.__score >= 90:
            return '优良'
        elif self.__score >= 60:
            return '及格'
        else:
            return '差'

n1 = Student('xiaoling',93)
n2 = Student('vforbox',65)
n3 = Student('xiaoyang',53)
n4 = Student('need_modify',98)
n1.print_score()
n2.print_score()
n3.print_score()
print('-----------------')
n4.set_name('change')
n4.set_score(55)
n4.print_score()

结果：

xiaoling : 93 - 优良
vforbox : 65 - 及格
xiaoyang : 53 - 差
-----------------
change : 55 - 差