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Python Python Collections (2016, retired 2019) Dungeon Game Movement

Wes House
Wes House
6,944 Points
Posted by Wes House
Wes House
6,944 Points

Why return x,y and not return player?

For the code below, the instructor deletes "return player" and replaces it with "return x,y" and the only explanation as to why is because he wants the values. But why can't it be "return player" since it's already set to x,y? Was that just an arbitrary decision?

def move_player(player, move): x,y = player 

if move == "LEFT":
    x -= 1
if move == "RIGHT":
    x += 1 
if move == "UP":
    y -= 1
if move == "DOWN":
    y += 1

return x,y

1 Answer

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

The code changes x and y based on the direction of the move. If you were to return "player", you're just giving back the same values you started with. By returning "x, y" you are giving back the new values after the move.

Pitrov Secondary
Pitrov Secondary
5,121 Points
Pitrov Secondary
Pitrov Secondary
5,121 Points

And because the player is a tuple and you can't change tuples? I am not sure, am I right?

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

You can't modify the tuple, but you could always assign "player" with a new one. But that's not necessary since you can just return a new one directly.

Jake Simpson
Jake Simpson
4,550 Points

Your answer makes sense, but I'm still a bit confused. I understand that just returning "player" in this function would give you back the original values, but how does the code know that "x, y" are the new values for player?

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

It's not the function itself that associates the return with "player", but the code where the function is called:

        player = move_player(player, move)

The calling code uses the tuple that the function returns and assigns the "player" variable with it.