Python中成员变量的Getter和Setter

Question

I know that it is not recommended to write getter and setter for class member variables in Python. Still I need to do it because I have a complex object which internally contains a lot of objects in depth. I need to expose a property/function in container object that will get and/or set member of inner object. How can I do this in Python?

def responseoperationcode(self,operationcode=None):
    if operationcode:
        self.innerobject.operationcode=operationcode
    else:
        return self.innerobject.operationcode

Above given function can act as a getter and setter but the syntax to use it would be confusing. My requirement is that user should get its value without using parenthesis and to set values he should pass parameters. Something like this

objectname.responseoperationcode ##this should return the value

and

objectname.responseoperationcode("SUCCESS")##this should set the value

Please suggest.

Answer 1

Python supports properties . You can change your code to:

@property
def responseoperationcode(self):
    return self.innerobject.operationcode

@responseoperationcode.setter    
def responseoperationcode(self, value):    
    self.innerobject.operationcode = value

Now you can use the responseoperationcode function like a field, eg:

objectname.responseoperationcode # this returns the value
objectname.responseoperationcode = "SUCCESS" # this sets the value

Answer 2

Well, if you have access to the definition of the inner objects, you could write a getter method there. Then whole thing would look similar to this:

class OuterObject:
    innerObject        

    def getInnerField(self, field=None):
        if field == None: 
            return self.innerObject.getField()
        else:
            self.innerObject.setField(field)



class InnerObject:
    field

    def getField(self):
        return self.field

    def setField(self, field):
        self.field = field