这是一个tic-tac-toe(井字棋，大叉或圆圈连成一直线的算赢）的代码，我的问题在enter_move函数的第5行，make_list_of_free_fields
函数的第6行
from random import randrange
def display_board(board):
print("+-------" * 3,"+",sep="")
for row in range(3):
print("| " * 3,"|",sep="")
for col in range(3):
print("| " + str(board[row][col]) + " ", end="")
print("|")
print("| " * 3,"|",sep="")
print("+-------" * 3,"+",sep="")
def enter_move(board):
ok = False# fake assumption - we need it to enter the loop
while not ok:
move = input("Enter your move: ")
ok = len(move) == 1 and move >= '1' and move <= '9'
"""
这里为什么不用integer来约定条件而要用str，譬如move<=9和>=1，我尝试了一下改成 "ok=move<=9 and move>=1" , 发现问题出在对角线，当对角线是同一个"X"或“O”，系统识别不出已经赢了这盘棋，但我不清楚为什么改成integer后会引起这个状况，请解答
"""
if not ok:
print("Bad move - repeat your input!")
continue
move = int(move) - 1 # cell's number from 0 to 8
row = move // 3 # cell's row
col = move % 3 # cell's column
sign = board[row][col] # check the selected square
ok = sign not in ['O','X']
if not ok: # it's occupied - to the input again
print("Field already occupied - repeat your input!")
continue
board[row][col] = 'O'# set '0' at the selected square
def make_list_of_free_fields(board):
free = [] # the list is empty initially
for row in range(3): # iterate through rows
for col in range(3): # iterate through columns
if board[row][col] not in ['O','X']: # is the cell free?
free.append((row,col)) # yes, it is - append new tuple to the list ，这里可以把元组(row,col)改成board[row][col]吗
return free
def victory_for(board,sgn):
if sgn == "X": # are we looking for X?
who = 'me' # yes - it's computer's side
elif sgn == "O": # ... or for O?
who = 'you' # yes - it's our side
else:
who = None # we should not fall here!
cross1 = cross2 = True # for diagonals
for rc in range(3):
if board[rc][0] == sgn and board[rc][1] == sgn and board[rc][2] == sgn: # check row rc
return who
if board[0][rc] == sgn and board[1][rc] == sgn and board[2][rc] == sgn: # check column rc
return who
if board[rc][rc] != sgn: # check 1st diagonal
cross1 = False
if board[2 - rc][2 - rc] != sgn: # check 2nd diagonal
cross2 = False
if cross1 or cross2:
return who
return None
def draw_move(board):
free = make_list_of_free_fields(board) # make a list of free fields
cnt = len(free)
if cnt > 0: # if the list is not empty, choose a place for 'X' and set it
this = randrange(cnt)
row, col = free[this]
board[row][col] = 'X'
board = [ [3 * j + i + 1 for i in range(3)] for j in range(3) ] # make an empty board
board[1][1] = 'X' # set first 'X' in the middle
free = make_list_of_free_fields(board)
human_turn = True # which turn is it now?
while len(free):
display_board(board)
if human_turn:
enter_move(board)
victor = victory_for(board,'O')
else:
draw_move(board)
victor = victory_for(board,'X')
if victor != None:
break
human_turn = not human_turn
free = make_list_of_free_fields(board)
display_board(board)
if victor == 'you':
print("You won!")
elif victor == 'me':
print("I won")
else:
print("Tie!")
还有就是里面那么多def函数，为什么有的没return一个值，像第2，5个函数就没有return一个值，应该要加一个return吗
