Hi, regenerate the whole object instead of a reset?
cheers, On Saturday, May 25, 2019, Irv Kalb <i...@furrypants.com> wrote: > 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
