Python while 循環內部 while 循環不會中斷

Question

這是一個井字游戲。 在本節中，function 檢查板上是否有未填充的單元格（第一個 while 循環，它工作），然后檢查 o 是否贏了（第二個 while 循環，它工作）。

如果 o 贏了，它會中斷循環並打印“yey o”。 檢查 x 是否贏了也是一樣，第三個循環也可以工作，只是當它中斷時，它將“恭喜 x”打印到無窮大。

我嘗試在第二個循環的級別上添加一個 break 語句（如“x won so break x, break o”）但沒有成功。我做錯了什么？

def place_marker():
    while any(isinstance(x, int) for x in board):
        while not win_check_o():
            while not win_check_x():
                # does stuff
            else:
                print("congrats x")
                break
        else:
            print("yey o")
            break

    print(board)

Answer 1

break語句僅從其包含循環中退出。 如果在內循環中有兩個嵌套循環和一個break語句，您將 go 回到外循環。

while True:
    while True:
        break
    print('This will repeat forever.')

要修復它，請將您的循環放入函數中並使用return語句。

Answer 2

break只從一個循環中中斷。 您應該將您的邏輯扁平化為一個循環 - 您可以制作一些布爾值並標記它們以記住完全爆發（非常糟糕的風格）：

a, SomeOtherCondition, thatCondition, SomeThing  = True, True, True, True

# contrieved bad example
while a and SomeOtherCondition:
    while a and thatCondition:
        while a and SomeThing:
            a = False
            print("Breaking")
            break
        # any code here will be executed once
        print("Ops") 
    # any code here will also be executed once
    print("Also ops")

輸出：

Breaking
Ops
Also ops

---

最好構造你的代碼並扁平化你的循環：

一些輔助方法

def any_tile_left(board):
    return any(isinstance(x, int) for x in board)  


def win_check(who, board):
    conditions = [(0,1,2),(3,4,5),(6,7,8), # horizontal
                  (0,3,6),(1,4,7),(2,5,8), # vertical
                  (0,4,8),(2,4,6)]         # diagonal
    for c in conditions:
        if all(board[i] == who for i in c):
            return True
    return False


def print_board(board):
    for row in range(0,9,3):
        print(*board[row:row + 3], sep = "   ")

游戲：

whos_turn = "X"
boardrange = range(1,10)
board = list(boardrange)

while True: 
    print_board(board) 
    try:
       pos = int(input(whos_turn + ": Choose a tile? "))
    except ValueError:
        print("impossible move. ", whos_turn,  "is disqualified and lost.")
        break

    if pos in boardrange and str(board[pos-1]) not in "XO":
        board[pos-1] = whos_turn
        if win_check(whos_turn, board):
            print(whos_turn, " won.")
            break
        whos_turn = "O" if whos_turn=="X" else "X"
    else:
        print("impossible move. ", whos_turn,  "is disqualified and lost.")
        break

    if not any_tile_left(board):
        print("Draw")
        break

它應該適用於井字游戲。 小心不要輸入不可能的東西，否則你會松懈。