[pygame] Initializing and Reinitializing Instance variables

[Irv Kalb <Irv@xxxxxxxxxxxxxx>]

Hi,

I am teaching an Python object-oriented programming class based on my own materials.  I am using Pygame to explain many OOP concepts.  So far its going very well.

I have built many small games as examples, but I keep running into a design dilemma.  I will often have a class, where I have an instance variable (I know it should be called an attribute!), and I want to be able to give it a starting value, but I also want to be able to reset it to the same value if the game is played more than once.  As a trivial example, here is the start of a Game class, that keeps track of the score of the game:

class Game:
    def __init__(self):
        self.score = 0

    def reset(self):
         self.score = 0

My main code instantiates a Game object and the game plays.  If the user wants to start the game over, I call the reset method.  There are two different problems with this approach:

  1) I am duplicating code.  This gets nasty when I have lots of instance variables to reset.
  2) Any time I want to change the "starting" value, I must make the identical change in both methods. 

The obvious solution is to have the __init__ method call the reset method:

class Game:
    def __init__(self):
         self.reset()

    def reset(self):
          self.score = 0

That does work fine and I like it.  But it breaks a general rule that you should declare all instance variables in the __init__ method.  I use PyCharm for the development of these games, and the "linter" (over the right side scroll bar) always flags this as a warning that a variable like this is not defined in my __init__ method.

I'm looking for a general solution that solves this.  The best I've come up with so far is to do something like this for each instance variable:

class Game:
    def __init__(self):
         self.score = None  # create the variable here, but only assign it a value in the reset method below
         self.reset()

    def reset(self):
          self.score = 0  # Supply the actual start value here.

Anyone have any other suggestions for how to do this cleanly?

Thanks,

Irv