Python 3 - 元组超出范围错误。但我正在使用字典？

Question

我的战舰计划中有一个超出范围的元组。我感到困惑的原因是我没有使用元组，除非我错了，我愿意纠正。元组不是可变的，这里引用的字典在启动程序时添加了项目。我是初学者所以如果我犯了一个愚蠢的错误，请不要判断！

from random import randint
#empty list to generate the board.
board = []
messages = {
  "win" : "Nooo you won!",
  "lose" : "Not my ship haha",
  "out" : "Oops, that's not even in the ocean.",
  "repeat" : "You guessed that one already"

}

ships = {
  'shiprows' : [0]
  'shipcols' : [0]
}

#generate board and append to board[] As of now it is a 10*10 grid.
for x in range(0, 10):
  board.append(["O"] * 10)

#prints the board every turn.
def print_board(board):
  for row in board:
    print(" ".join(row))

print_board(board)

#computer chooses where to put battleships' rows
def random_row1(board):
  return randint(0, len(board) - 1)

def random_col1(board):
 return randint(0, len(board) - 1)
#calling above two functions and storing their values for 5 ships.
#creating variables for 5 ships.
vars = 0
for vars in range(0, 5):
  print(vars)
  if len(ships.keys()) >= 4:
    while ships["shiprow{}".format(vars - 2)] == ships["shiprow{}".format(vars - 1)] and ships["shipcol{}".format(vars - 2)] == ships["shipcol{}".format(vars - 1)]:
      ships["shiprow{}".format(vars)] = random_row1(board)
      ships["shipcol{}".format(vars)] = random_col1(board)
    ships["shiprow{}".format(vars)] = random_row1(board)
    ships["shipcol{}".format(vars)] = random_col1(board)
  else:
    ships["shiprow{}".format(vars)] = random_row1(board)
    ships["shipcol{}".format(vars)] = random_col1(board)


#program itself
turn = 0
#enforces four turns before game over. Will possibly extend to unlimited with multiple ships.
print(ships)
for turn in range(20):
  turn = turn + 1
  print ("Turn {}".format(turn))
  print ("Ships Left: {}".format(int(len(ships.keys()) / 2))) 
  guess_row = int(input("Guess Row: "))
  guess_col = int(input("Guess Col: "))

#checking stuff.
  i = 0
  if guess_row == ships["shiprow{}".format(i = range(0, 10))] and guess_col == ships["shipcol{}".format(i)]:
    print (messages["win"])
    board[guess_col][guess_row] = u"#"
    print_board(board)

  elif board[guess_col][guess_row] == "X":
    print ("You guessed that one already.")
  elif guess_row not in range(len(board)) and guess_col not in range(len(board[0])):
    print(messages["out"])
  else:
    print(messages["lose"])
    board[guess_col][guess_row] = "X"
    print_board(board)
  if turn >= 20:
    print ("Game Over")
    board[ships["ship_col{}".format(range(0, 10))]][ships["ship_row{}".format(range(0, 10))]] = u"#"
    print_board(board)
    break

可疑线似乎是第62行 - 这个看起来很粗略，但我实际上并不知道该怎么做。请告知该怎么做：BTW这里是错误：

Traceback (most recent call last):
  File "battleship3.py", line 62, in <module>
    if guess_row == ships["shiprow{}".format(i = range(0, 10))] and guess_col == ships["shipcol{}".format(i)]:
IndexError: tuple index out of range

谢谢。

Answer 1

每当您使用具有位置格式规范的格式字符串（如{}或{1}）时，您都会收到此错误消息，但只传递关键字参数。

类似地，当您使用仅包含关键字格式规范（如KeyError）的格式字符串时，您会获得{v}，但只传递位置参数：

>>> '{}'.format(i=1)
IndexError: tuple index out of range
>>> '{i}'.format(1)
KeyError: 'i'

修复只是为了使您的规范与您的参数匹配。无论你喜欢哪种方式都很好，他们只需要保持一致：

>>> '{i}'.format(i=1)
1
>>> '{}'.format(1)
1

---

话虽如此，我不确定这是什么意思：

"shiprow{}".format(i = range(0, 10))

你可以用任何一种方式修复它，但这真的是你想要的字符串吗？

>>> "shiprow{i}".format(i = range(0, 10))
'shiprowrange(0, 10)'
>>> "shiprow{}".format(range(0, 10))
'shiprowrange(0, 10)'

---

如果你很好奇为什么会出现这个错误，过度简化format，它的工作原理如下：

def format(self, *args, **kwargs):
    result = ''
    index = 0
    bits = self.parse_format_stuff()
    for bit in bits:
        if bit is a regular string:
            result += bit
        elif bit is empty braces:
            result = args[index]
            index += 1
        elif bit is a number in braces:
            result += args[number]
        elif bit is a valid identifier string in braces:
            result += kwargs[identifier]
        else:
            raise a ValueError
    return result

所以，当它看到{}格式规范时，它会寻找args[0]。由于你没有传递任何位置参数，args是空元组()，所以args[0]是IndexError。

可以说，如果format处理这些错误并将它们变成更好的东西可能会更好 - 但偶尔能够以编程方式处理KeyError是有用的。 （不常见的是IndexError，但显然两者必须以同样的方式工作。）

Answer 2

获得：

Traceback (most recent call last):
File "shiptest.py", line 51, in <module>
ships['shiprows'][vars] += random_row1(board)
IndexError: list index out of range

从var = 0之后的所有内容更改为：

vars = 0
for vars in range(0, 5):
  print(vars)
  ships['shiprows'][vars] = random_row1(board)
  ships['shipcols'][vars] = random_col1(board)
  print(ships)

我想我在字典中的列表是错误的。我应该使用.append（）吗？编辑：我用.append（）我是个白痴。它现在正在工作，谢谢你的帮助！