UnboundLocalError：无法访问未与值关联的局部变量“currentPlayer”

Question

我不明白这个错误。 'currentPlayer' 在第 13 行声明和定义，它存在于全局。为什么它在我的 ToggleTurn() 方法中未绑定？

错误：

Traceback (most recent call last):
  File "...main.py", line 83, in <module>
    PlacePiece(currentPlayer,5)
  File "...main.py", line 51, in PlacePiece
    ToggleTurn()
  File "...main.py", line 28, in ToggleTurn
    if currentPlayer == 1:
       ^^^^^^^^^^^^^
UnboundLocalError: cannot access local variable 'currentPlayer' where it is not associated with a value

import pygame as pg
pg.init()

currentPlayer = 2 # 1 = o and 2 = x

def ToggleTurn():
    if currentPlayer == 1:
        currentPlayer = 2
    elif currentPlayer == 2:
        currentPlayer = 1
    else:
        print("ERROR: Could not progress to the next turn!")
        return False
    return True

def PlacePiece(piece,slot):
    if not (1,slot) in pieceList or not (2,slot) in pieceList:
        pieceList.append((piece,slot))
        ToggleTurn()
    else:
        print("GAME NOTE: A piece has already been placed there!")



RUN = True
while RUN:
    #event handler
    for event in pg.event.get():
        if event.type == pg.QUIT:
            RUN = False
        if event.type == pg.KEYDOWN:
            if event.key == pg.K_KP1:
                PlacePiece(currentPlayer,1)
            #elif for the other numpad buttons
    pg.display.update()

我尝试按值传递 currentPlayer 但随后 TogglePlayer() 方法仅更新局部变量。

Answer 1

该值不是全局的。要使其全局化，您必须在“

global currentPlayer

”行之后添加一行“

def ToggleTurn

”，以便修改函数中的值。如果您只想获得

currentPlayer

的值，那么您可以在代码的最开头添加行

glibal currentPlayer

。

在投反对票之前，请在评论中写下原因。我可以让我的答案更好。