Mdthbs

I am currently learning Python. Since I am a big fan of OO (object-oriented) programming, obviously it's not hard to apply it in Python. But when I tried it, it seems very different to C#.

As you can see below, I am trying to create a character class, with three attributes Id, Hp, and Mana. The score is calculated by adding up Hp and Mana and then times 10.

As you can see, after defining MyChar where id=10 hp=100 mana=100, I was expecting MyChar.Score is (100+100)*10, which is 2000, but weirdly, it says:

bound method Character.Score of <__main__.Character object at 0x0000021B17DD1F60> as the result of print(MyChar.Score).

How can I fix this problem?

Here is my code:

class Character:



    def __init__(self, Id, Hp, Mana):

        self.Id = Id;

        self.Hp = Hp;

        self.Mana = Mana;





    def Score(self):

        return (self.Hp + self.Mana)*10;



MyChar = Character(10, 100, 100);



print(MyChar.Score)

Use it like any other function by calling it. Note the extra pair of parentheses below.

print(MyChar.Score())

The pair of parentheses following MyChar.Score are needed to invoke the __call__() magic method, calling the function. Without these parentheses, only the representation of the method, repr(MyChar.Score), was printed.

If you want to use it like a property in C#, decorate the function with @property, like so:

class Character:



    def __init__(self,Id,Hp,Mana):

        self.Id=Id;

        self.Hp=Hp;

        self.Mana=Mana;



    @property

    def Score(self):

        return (self.Hp+self.Mana)*10;



MyChar=Character(10,100,100);



print(MyChar.Score)

So you don't have to call it like a function.

For more advanced usage of properties (e.g. also having a setter func), see the official docs: https://docs.python.org/3/library/functions.html#property

In Python, everything is an object, including classes, functions and methods, so MyChar.Score (without the parens) only resolves the Score attribute on MyChar object. This yields a method object, which happens to be a callable object (an object that implements the __call__ special method). You then have to apply the call operator (the parens) to actually call it.

You may want to check the official documentation for more on Python's object model.

class Character(object):

    def __init__(self):

        print ('Starting')



    def method(self):

        print ('This is a method()')

ch = Character()

'''When we dont add the bracket after the method call it would lead to method bound error as in your case'''

print (ch.method)

'''This can be solved by doing the following line'''

ch.method()