在Python中，我们在属性名称之前使用双下划线（Or __），并且这些属性在外部不会直接可见。
class MyClass:
# Hidden member of MyClass
__hiddenVariable = 0
# A member method that changes
# __hiddenVariable
def add(self, increment):
self.__hiddenVariable += increment
print (self.__hiddenVariable)
# Driver code
myObject = MyClass()
myObject.add(2)
myObject.add(5)
# This line causes error
print (myObject.__hiddenVariable)
输出 :2
7
Traceback (most recent call last):
File “filename.py”, line 13, in
print (myObject.__hiddenVariable)
AttributeError: MyClass instance has
no attribute ‘__hiddenVariable’