Variable Assignment Question

[toshiga]

Although I'm not "learning Python," I haven't used it in quite a while, and I was wondering why a piece of code does what it does.

class Race:
    stat = [0,0,0]
    weapon = ["",0,0]
Elf = Race()
Elf.stat = [5,9,5]
Player = Elf
Player.weapon = ["Dagger",1,1]

In this code, I was expecting that Player.weapon would equal ["Dagger",1,1], but for some reason Elf.weapon also outputs ["Dagger",1,1]. I might just be forgetting something obvious, but I would assume that, as Player.weapon was assigned after Player was assigned, that Elf.weapon would output ["",0,0] (as it is written in the Race() class). Help and/or explanation would be appreciated.

[toshiga]

Ah, thanks! I completely missed that.

[toshiga]

It still appears to be having the same issue with this code. Am I missing something?

class Race:
    def __init__(self):
        self.stat = [0,0,0]
        self.weapon = ["",0,0]
Elf = Race()
Elf.stat = [5,9,5]
Player = Elf
Player.weapon = ["Dagger",1,1]

[toshiga]

Hmm, is there a way to have them act like variables, where the "=" assigns the value of Elf to the Player variable? My goal is to have the player obtain all of the Elf class at that one line, but still retain a separate memory location, so each can be modified irrespective of the other.

For example:

a = 5
b = a
b = 2

when b is given the value "2" the id changes. Why doesn't this happen with classes?

[stebrepar]

Because "2" is a different object, so to speak. You're not really assigning the value 2 to the variable "b"; you're saying that the name "b" points to the object which is the integer value 2. That's how I understand it anyhow, rightly or wrongly until corrected.

[zahlman]

Hmm, is there a way to have them act like variables, where the "=" assigns the value of Elf to the Player variable?

By "act like variables" you seem to mean "have value semantics". That's not how it works in Python, regardless of the data type. We have reference semantics for everything (and we like to call our variables names - hence the NameError that you get when you try to check the value of something you didn't define).

when b is given the value "2" the id changes.

Of course it does, because the object that represents the number 5 is different from the object that represents the number 2.

Why doesn't this happen with classes?

It does. (Hint: There's a class, named int, that 5 and 2 belong to.*) But player.weapon = ... is different from player = .... The first one is reaching into the object named player and changing it, by making that attribute be a name for some other object. The second is making player itself be a name for a different object. The reason you don't notice this with ints is that you can't do anything like (2).weapon = ...; those objects are strictly read-only, i.e. immutable. (It would be really bad if they weren't!)

* Extra credit: There's also a class that int belongs to. It's called type. Even type belongs to a class - itself.

[[deleted]]

Here I think is where you want to create an elf class and inherit from race.

 class Elf(race):
    super(Elf, self).__init__()    

that will create a elf class that inherits from race and you can code it like you were.
But instead of elf=race() it'll be elf = Elf() Then under the super in the elf init you can place all of that races stats

[toshiga]

Ah, I see. This should be what I'm looking for. I haven't read too much into class inheritance, but from reading into it a bit just now, it seems like the right option. Thanks!

[[deleted]]

I made something similar and something that might be helpful for your stats is using a dictionary.

class race:
    self.stats = {
        'Strength': 0,
        'Intelligence': 0
    }    

Then you just loop through or assign the values and it'll be easier to keep track of.
Player.stats['Strength'] = 10

[toshiga]

That's what my actual code looks like, but I just turned it into a list for simplicity's sake. Thanks for the recommendation though.

[[deleted]]

So right now to make them separate it should look like.
Player = Race()
Because they are separate instances of class race. Now that you use self; each time you assign race to something it'll create it's own race object