Python 20×2人机棋盘游戏报错求助：IndexError索引越界

问题背景 #

我正在开发一款人类玩家与电脑对战的20×2棋盘游戏，这是一款需使用骰子的简易棋盘游戏。运行代码时触发了IndexError: list index out of range错误，无法定位问题所在，恳请帮助排查修复。

报错信息 #

Traceback (most recent call last):
  File "c:\Users\abiruk\Downloads\main.py", line 77, in <module>
    move_pawn('human', dice)
  File "c:\Users\abiruk\Downloads\main.py", line 48, in move_pawn
    if board[row][pos] == 'X':
IndexError: list index out of range

问题代码 #

import random
import datetime

# initialize the game board
board = [['-' for _ in range(20)] for _ in range(2)]
board[0][0] = 'X'  # human player
board[1][0] = 'X'  # computer

# initialize variables
turn = 1  # human player goes first
human_pos = 0
computer_pos = 0
human_moves = 0
computer_moves = 0
human_hits = 0
computer_hits = 0

# function to print the game board
def print_board():
    print('+----' * 20 + '+')
    for row in range(2):
        for col in range(20):
            print('|', board[row][col], ' ', end='')
        print('|')
        print('+----' * 20 + '+')

# function to roll the dice
def roll_dice():
    return random.randint(1, 6)

# function to move the player's pawn
def move_pawn(player, steps):
    global human_pos, computer_pos
    if player == 'human':
        pos = human_pos
        row = 0
    else:
        pos = computer_pos
        row = 1
    board[row][pos] = '-'
    pos += int(steps/2)
    if pos >= 20:
        pos = 20
    if player == 'human':
        human_pos = pos
    else:
        computer_pos = pos
    if board[row][pos] == 'X':
        pos = 0
        board[row][pos] = 'X'
        if player == 'human':
            human_hits += 1
        else:
            computer_hits += 1
    else:
        board[row][pos] = 'X'

# function to check if a player has won
def check_win(player):
    if player == 'human':
        pos = human_pos
    else:
        pos = computer_pos
    if pos >= 20:
        return True
    else:
        return False

# main game loop
while True:
    print_board()
    if turn == 1:
        input('Press Enter to roll the dice')
        dice = roll_dice()
        print('You rolled a', dice)
        if dice == 6:
            move_pawn('human', dice)
            print_board()
            input('Press Enter to start the game')
            turn = 2
        else:
            print('You need to roll a 6 to start the game')
    else:
        dice = roll_dice()
        print('Computer rolled a', dice)
        if dice == 6:
            move_pawn('computer', dice)
            print_board()
            input('Press Enter to start the game')
            turn = 1
        else:
            move_pawn('computer', dice)
            print_board()
            if check_win('computer'):
                print('Computer wins!')
                break
            turn = 1
            input('Press Enter to continue')

    if check_win('human'):
        print('You win!')
        break

# count the number of moves and hits for each player
human_moves = human_pos + human_hits
computer_moves = computer_pos + computer_hits

# save the game session to a text file
date_time = datetime.datetime.now().strftime('%Y_%m_%d_%H_%M')
filename = date_time + '.txt'
with open(filename, 'w') as f:
    f.write('Human\n')
    f.write('Total moves: ' + str(human_moves) + '\n')
    f.write

问题分析 #

报错的核心原因是：棋盘每行只有20个元素，列索引范围是0-19，但在move_pawn函数中，当pos >=20时直接将pos设为20，后续访问board[row][20]会超出列表索引范围，触发IndexError。

另外还有两处隐藏问题：

1. move_pawn中修改human_hits和computer_hits时未声明全局变量，会触发UnboundLocalError
2. 最后写入文件的代码不完整，f.write没有实际内容

修复方案 #

1. 修正move_pawn函数逻辑 #

def move_pawn(player, steps):
    global human_pos, computer_pos, human_hits, computer_hits
    if player == 'human':
        pos = human_pos
        row = 0
    else:
        pos = computer_pos
        row = 1
    
    # 计算新位置
    new_pos = pos + int(steps/2)
    
    # 若到达或超出终点，直接更新位置并返回（不操作棋盘）
    if new_pos >= 20:
        if player == 'human':
            human_pos = new_pos
        else:
            computer_pos = new_pos
        return
    
    # 未到达终点，先清除旧位置
    board[row][pos] = '-'
    
    # 检查新位置是否有己方棋子
    if board[row][new_pos] == 'X':
        new_pos = 0
        board[row][new_pos] = 'X'
        if player == 'human':
            human_hits += 1
        else:
            computer_hits += 1
    else:
        board[row][new_pos] = 'X'
    
    # 更新玩家位置
    if player == 'human':
        human_pos = new_pos
    else:
        computer_pos = new_pos

2. 补全文件写入代码 #

# save the game session to a text file
date_time = datetime.datetime.now().strftime('%Y_%m_%d_%H_%M')
filename = date_time + '.txt'
with open(filename, 'w') as f:
    f.write('Human\n')
    f.write('Total moves: ' + str(human_moves) + '\n')
    f.write('Total hits: ' + str(human_hits) + '\n\n')
    f.write('Computer\n')
    f.write('Total moves: ' + str(computer_moves) + '\n')
    f.write('Total hits: ' + str(computer_hits) + '\n')

3. 修正主循环规则逻辑（可选优化） #

原代码中电脑未掷出6时直接移动，不符合“掷6才能开始”的规则，可调整电脑回合逻辑：

else:
    dice = roll_dice()
    print('Computer rolled a', dice)
    if dice == 6:
        move_pawn('computer', dice)
        print_board()
        input('Press Enter to continue')
        turn = 1
    else:
        print('Computer needs to roll a 6 to start moving')
        input('Press Enter to continue')
        turn = 1

内容的提问来源于stack exchange，提问作者abhiruk prashan