访问限制

在class内部,可以有属性和方法,而外部代码可以通过直接调用实例方法来操作数据,

这样,就隐藏了内部的复杂

class Student(object):

    def __init__(self, name, score):
        self.name = name
        self.score = score

    def print_score(self):
        print '%s: %s' % (self.name, self.score)

bart = Student('Bart Simpson', 98)
print bart.name
print bart.score
bart.score = 59
print bart.score

C:Python27python.exe C:/Users/TLCB/PycharmProjects/untitled/a2.py
Bart Simpson
98
59

class Student(object):

    def __init__(self, name, score):
        self.name = name
        self.score = score

    def print_score(self):
        print '%s: %s' % (self.name, self.score)
bart = Student('Bart Simpson', 98)
print bart.name

C:Python27python.exe C:/Users/TLCB/PycharmProjects/untitled/a2.py
Bart Simpson

class Student(object):

    def __init__(self, name, score):
        self.__name = name
        self.__score = score

    def print_score(self):
        print '%s: %s' % (self.__name, self.__score)
bart = Student('Bart Simpson', 98)
print bart.name

C:Python27python.exe C:/Users/TLCB/PycharmProjects/untitled/a2.py
Traceback (most recent call last):
  File "C:/Users/TLCB/PycharmProjects/untitled/a2.py", line 10, in <module>
    print bart.name
AttributeError: 'Student' object has no attribute 'name'

Process finished with exit code 1