Question

所以我正在学习使用Learn python的python。我正在努力开发一个库存系统。目标是将其构建为一个将由房间类拉出的类。我将使用字典作为库存，这样当我为每个房间创建库存时，我可以说出它们在房间里的位置。

所以在卧室里，我可以说床上有一把刀，而不只是说你看到刀，蜡烛，油。

现在，当有人说拿刀时，我正在努力拿起物品。我能够做一个奇怪的搜索，并将该值设置为无，以便当有人在房间里看起来它没有显示但我似乎遇到了范围问题。我在这个网站上阅读了多个其他问题，因为它是一个可变对象，我不需要做全局字典，当我尝试它有错误。我能够编辑对象但是当我退出我的if语句并且for循环时它不会继续。

请帮帮我:)。

#This is the inventory in this room
inventory = {'desk': 'Miniature Fusion Warhead',  
         'bed':'knife', 'sink':None}        
def take(item):
    if item in inventory.itervalues():
        #add_item_to_inventory(item)

        for key, value in inventory.iteritems():

            if value == item:
                print ("Wow.\n"
                    "Look at you.\n"
                    "Picking shit up and everything.")
                value = None


    else:
        print ("What do you think this is?"
            "  The dollar store?  We don't "
            "got that shit here!")


# Prints out what items are in the room.  
# I am hoping to later come up with an idea for how
# To make different variations of this, and have it randomly
# pick between the different ways it says what it sees.
for key, value in inventory.iteritems():
    if value != None:
        print "You see a %s on the %s." % (value, key)
print "What do you want to pick up?"
ui = raw_input(">")
split_ui = ui.split()
print split_ui

if len(split_ui) > 1:
    if split_ui[0] == "take":
        print ("You reach over to grab the %s."
            "\n...") % split_ui[1]
    take(split_ui[1])

    else:
        print ("What you talking bout Willis?  "
            "Don't you know this is just about "
            "takin shit.")
else:
    print ("Who taught you how to talk?"
        "\n...\nLet me show you how its done.\n"
        "Use a verb, like take, then throw in an "
        "object like knife.")

print inventory

这是我给出的输出。

You see a knife on the bed.
You see a Miniature Fusion Warhead on the desk.
What do you want to pick up?
>take knife
['take', 'knife']
You reach over to grab the knife.
...
Wow.
Look at you.
Picking shit up and everything.
{'sink': None, 'bed': 'knife', 'desk': 'Miniature Fusion Warhead'}

重要提示：目前只有你拿刀而不是弹头才有效。我需要找出具有多个单词的项目的另一种解决方案。

谢谢！

Answer 1

循环中的value与字典的实际值不同。它只是对该值的引用，因此当您执行value = None实际更改时保存新值None的引用值，而不是字典值。

为了更好地展示它，这是在for key, value in inventory.iteritems():

内的作业之前

-------            -------------------------
|value|   -------> |value of the dictionary|
-------            -------------------------

这是在value = None

之后

                   -------------------------
                   |value of the dictionary|
                   -------------------------
-------            ------
|value|   -------> |None|
-------            ------

正如您所看到的，字典值不会改变。只有value循环的变量for 变化。此变量属于for循环的范围，之后将被丢弃。

替代value = None代替：

inventory[key] = None

Answer 2

zbs是正确的，你只是将指针的值改为dict值。但是，你这样做太难了：

#This is the inventory in this room
inventory = {'Miniature Fusion Warhead': 'desk',
             'knife':'bed'}
player_inventory = set()

def take(item):
  if item in inventory:
    print("You picked up the {}".format(item))
    player_inventory.add(item)
    del inventory[item]

  else:
    print("That item doesn't exist")

while True:
  print('')
  print("Inventory: " + ', '.join(player_inventory))
  for k,v in inventory.items():
    print("You see a {} on the {}".format(k, v))

  print("What do you want to pick up?")
  ui = raw_input("> ").split()
  verb = ui[0]
  item = ' '.join(ui[1:])
  if verb == 'take':
    if item:
      print("You take the {}".format(item))
      take(item)
    else:
      print("That item doesn't exist")
  else:
    print("That's not an action")

for循环分配中的字典值不会更改

2 个答案: