python3基础——访问限制

前提：类中的属性不想被外界修改，则可以将属性变成私有变量，前面用__标记

class Student:
"""docstring for Student"""
def __init__(self, name, score):
self.__name = name  #__name为该类的私有变量，不可以被外界直接调用，可以借助方法获得
self.__score = score


def getName(self):
return self.__name


def getScore(self):
return self.__score

if __name__ == '__main__':
st = Student("yanghui",80)

print("%s: %s" %(st.getName(),st.getScore()))

练习：请把下面的Student对象的gender字段对外隐藏起来，用get_gender()和set_gender()代替，并检查参数有效性：

class Student(object):
    def __init__(self, name, gender):
        self.name = name

        self.gender = gender

# 测试:
bart = Student('Bart', 'male')
if bart.get_gender() != 'male':
    print('测试失败!')
else:
    bart.set_gender('female')
    if bart.get_gender() != 'female':
        print('测试失败!')
    else:
        print('测试成功!')

答案：

class Student:

"""docstring for Student"""
def __init__(self, name, gender):
self.__name = name  #__name为该类的私有变量，不可以被外界直接调用，可以借助方法获得
self.__gender = gender


def set_gender(self,gender):
if gender in ['male', 'female']:
self.__gender = gender
else:
print("input error")



def get_gender(self):
return self.__gender

if __name__ == '__main__':
st = Student("yanghui",'male')
if st.get_gender() != 'male':
print('测试失败!')
else:
st.set_gender('llll')
print(st.get_gender())
if st.get_gender() != 'female':
print('测试失败!')
else:
print('测试成功!')