python print board game - 为什么即使板子没有满，代码也会结束？

Question

我在下面有此代码作为 python 棋盘游戏的一部分 - 为什么即使棋盘未满，代码也会结束？

drop_piece 函数代码应该一直运行到板子已满，但最后的板子未满。

import random


ROWS       = 6
COLUMNS    = 7

PIECE_NONE = '  '
PIECE_ONE  = 'x'
PIECE_TWO  = 'o'



# Board Functions
def create_board(rows=ROWS, columns=COLUMNS):
    ''' Creates empty Connect 4 board '''
    board = []

    for row in range(rows):
        board_row = []
        for column in range(columns):
            board_row.append(PIECE_NONE)
        board.append(board_row)

    return board






def print_board( board ):
    ''' Prints Connect 4 board '''
    for row in board:    # like for i in list,  the board has 6 items or rows, 
        print ('| ' + ' | '.join(row) + ' |')    # front and end has a '|',  in the middle, for each row which has 7 items, join the 7 items by each '|', now it prints 7 slots.


print("\n---------print:   7 items, join the 7 items by each '|', now it prints 7 slots--------------\n" )
#print_board( create_board( ) )







def drop_piece(board, column, piece):   
    ''' Attempts to drop specified piece into the board at the
    specified column

    If this succeeds, return True, otherwise return False.
    '''

    for row in reversed(board):  # reverse the board
        if row[column] == PIECE_NONE:   # if each row from bottom to top, row[column] blank, drop ball, if not, what about the next one, i.e. second last row, 
            row[column] = piece
            return True    # this code should run until the board is FULL, but the board at last is NOT FULL.

    return False





print("\n---------print while drop_piece( )------------\n" )

import random

Board = create_board()
Turn=0
Players=(PIECE_ONE, PIECE_TWO)

while drop_piece(Board, random.randint(0, COLUMNS - 1), Players[Turn % 2]):   
# while drop_piece( ) is True:
    print_board(Board)
    print()
    Turn += 1
    
    
print ('Board FULL!')

下面是输出的最后一部分。董事会未满。 drop_piece 代码应该一直运行到板子满为止，对吧？但它没有。

|    |    |   |   |   | o |   |
|    |    | x | x |   | o |   |
|    |    | x | x |   | o |   |
|    |    | o | o | x | o | x |
|    |    | o | x | x | x | o |
| o  |    | x | o | o | x | x |

Board FULL!

Answer 1

当一列填满时，您的代码会返回“无”，这相当于 python 中的 False。我已修改您的代码以跟踪该列，并且仅在所有列已满时才返回 false。

import random


ROWS       = 6
COLUMNS    = 7

PIECE_NONE = ' '
PIECE_ONE  = 'x'
PIECE_TWO  = 'o'
FULL_COLUMS = ["has_space"] * COLUMNS # List to keep track of full colums


# Board Functions
def create_board(rows=ROWS, columns=COLUMNS):
    ''' Creates empty Connect 4 board '''
    board = []

    for row in range(rows):
        board_row = []
        for column in range(columns):
            board_row.append(PIECE_NONE)
        board.append(board_row)

    return board






def print_board( board ):
    ''' Prints Connect 4 board '''
    for row in board:    # like for i in list,  the board has 6 items or rows,
        print ('| ' + ' | '.join(row) + ' |')    # front and end has a '|',  in the middle, for each row which has 7 items, join the 7 items by each '|', now it prints 7 slots.


print("\n---------print:   7 items, join the 7 items by each '|', now it prints 7 slots--------------\n" )
#print_board( create_board( ) )







def drop_piece(board, column, piece):
    ''' Attempts to drop specified piece into the board at the
    specified column

    If this succeeds, return True, otherwise return False.
    '''

    ''' ************** Debug Notes  ************************
        Your code in this loop will and return None once the given 'column' is full. This is your bug :)
        To correct it, you would need to check if all columns are full, and only then do you return full.
        
        ***There are several ways of doing this. I will use the simplest one. So, I will keep track of every full colums.
        Therefore, every time the for loop is exectuted to completion, I will take the value of 'column' and mark that 
        the column corespoding to that number is full. I will keep doing this until all colums are full.
        To return false, all columns will need to be full. 
    '''
    for row in reversed(board):  # reverse the board
        if row[column] == PIECE_NONE:   # if each row from bottom to top, row[column] blank, drop ball, if not, what about the next one, i.e. second last row,
            row[column] = piece
            return True    # this code should run until the board is FULL, but the board at last is NOT FULL.
    #if we get here, one of the colums if full, so lets mark that
    FULL_COLUMS[column] = "Full"
    return "has_space" in FULL_COLUMS # this will return false only if all colums are full





print("\n---------print while drop_piece( )------------\n" )

import random

Board = create_board()
Turn=0
Players=(PIECE_ONE, PIECE_TWO)

while drop_piece(Board, random.randint(0, COLUMNS - 1), Players[Turn % 2]):
# while drop_piece( ) is True:
    print_board(Board)
    print()
    Turn += 1


print ('Board FULL!')

这是我修改后得到的输出

| o | o | o | x | x | x | o |
| x | o | o | o | o | x | x |
| x | o | x | o | x | o | o |
| o | x | o | o | o | x | x |
| x | o | o | x | x | x | o |
| o | x | o | o | x | x | x |

Board FULL!

Answer 2

drop piece 函数只测试使用该函数输入的列的所有行，而不是所有列的所有行。因此，当指定列已满时，droppiece 函数将返回 False。为了测试整个板子何时已满，您必须使用另一个函数来测试它，如下所示：

def board_is_not_full():
    for row in board:
        for column in row:
            if row[column] == PIECE_NONE:
                return True
    return False