如何使怪物移动？

Question

It says this

Traceback (most recent call last):
File "dungeon2.py", line 93, in <module>
move_monster(monster, steps)
NameError: name 'steps' is not defined

When the game starts, the monster stays in it's position but I'm not sure why.

import random

BOARD = [(0, 0), (0, 1), (0, 2),
         (1, 0), (1, 1), (1, 2),
         (2, 0), (2, 1), (2, 2)]

def get_locations():
  monster = random.choice(BOARD)
  start = random.choice(BOARD)
  door = random.choice(BOARD)

  #If player, door or monster are random, do it all over again.
  if monster == door or monster == start or door == start:
    return get_locations()

  return monster, door, start

def move_player(player, move):
  x, y = player
  if move == 'LEFT':
    y -= 1
  elif move == 'RIGHT':
    y += 1
  elif move == 'UP':
    x -= 1
  elif move == 'DOWN':
    x +=1
  else:
    print("That move doesn't exist PLEASE.")
  return x, y

def move_monster(monster, steps):
  x, y = monster
  moves = ['LEFT', 'RIGHT', 'UP', 'DOWN']
  steps = random.choice(moves)
  if steps == 'LEFT':
    y -= 1
  elif steps == 'RIGHT':
    y += 1
  elif steps == 'UP':
    x -= 1
  elif steps == 'DOWN':
    x +=1  


def get_moves(player):
  moves = ['LEFT', 'RIGHT', 'UP', 'DOWN']
  if player[1] == 0:
    moves.remove('LEFT')
  if player[1] == 2:
    moves.remove('RIGHT')
  if player[0] == 0:
    moves.remove('UP')
  if player[0] == 2:
    moves.remove('DOWN')
  return moves


def draw_map(player, monster):
  print('_ _ _')
  tile = '|{}'  
  for idx, cell in enumerate(BOARD):
    if idx in [0, 1, 3, 4, 6, 7]:
      if cell == player:
        print(tile.format("X"), end ='') 
      elif cell == monster:
        print(tile.format("M"), end = '')
      else:
        print(tile.format("_"), end ='')
    else:
      if cell == player:
        print(tile.format("X|"))
      elif cell == monster:
        print(tile.format("M|"))
      else:
        print(tile.format("_|"))    


monster, player, door = get_locations()

print("Welcome to the dungeon! *evil laugh*")

while True:
  moves = get_moves(player)

  draw_map(player, monster)              
  print("You are currently in room {}".format(player)) #fill in with player position
  print("You can move {}".format(moves)) # fill in with available positions
  print("Enter 'GIVEUP' to quit")

  move = input("> ")
  move = move.upper()
  move_monster(monster, steps)                                       LINE 93

  if move == "GIVEUP":
      print("Giving up, you wait sadly for the Beast to find you. It does, and makes a tasty meal of you...")
      print("You lose.")
      break

  if move in moves:
        player = move_player(player, move)
  else:
        print("Walls are hard, stop walking into them!")
        continue
  if player == door:
    print("You narrowly escaped the beast and escaped")
    print("You win!")
    break
  elif player == monster:
    print("The beast found you!")
    print("You lose!")
    print("Game over")
    break
  # If it's a good move, change the player's position
  # If it's a bad move, don't change anything
  # If the new position is the door, they win!
  # If the new positon is the Beast's, they lose!      
  # Otherwise, continue

and it looks like this

|X|_|_|                                                                                                                     
|_|_|_|                                                                                                                     
|_|_|M|  where M is player and X is monster

Answer 1

>>> monster = (2,3)
>>> x,y=monster
>>> x+=1
>>> x, y
(3, 3)
>>> monster
(2, 3)

As you can see here, assigning the monster's position to new variables and changing the new variables does not change the original monster's position. After changing the function to not take steps as a parameter (as explained in Mureinik's answer), you would have to move the monster the way you did with the player, by changing your code to the following:

def move_monster(monster):
  x, y = monster
  moves = ['LEFT', 'RIGHT', 'UP', 'DOWN']
  steps = random.choice(moves)
  if steps == 'LEFT':
    y -= 1
  elif steps == 'RIGHT':
    y += 1
  elif steps == 'UP':
    x -= 1
  elif steps == 'DOWN':
    x +=1
  return x,y

and

monster = move_monster(monster)

Answer 2

There's no point in passing steps to move_monster , as you overwrite it in the third line, and never use the original value. Just drop it from the function's definition:

def move_monster(monster):
  # here ---------------^
  x, y = monster
  moves = ['LEFT', 'RIGHT', 'UP', 'DOWN']
  steps = random.choice(moves) # steps is now a local variable
  if steps == 'LEFT':
    y -= 1
  elif steps == 'RIGHT':
    y += 1
  elif steps == 'UP':
    x -= 1
  elif steps == 'DOWN':
    x +=1  

And stop trying to pass it when you call the function:

move_monster(monster)
# here -------------^