循环体是否改变了我的调用方法？ (新白)

Question

所以我对任何类型的编程都是全新的。 我正在学习 Python 入门课程，该课程要求学生提供在一组房间中走动的代码。 我认为从布局中分配一些字典并从那里开始是个好主意。 当我尝试在第一次分配命令时调用键的值时，它按预期工作。 但是当我在两行之后执行相同的精确操作时，我得到一个类型错误。 我难住了。

rooms = {
    'r1': {'name': 'Room1', 'north': 'room7', 'east': 'room2', 'item': 'ob1'},
    'r2': {'name': 'Room2', 'west': 'room1', 'item': 'ob2'},
    'r3': {'name': 'Room3', 'north': 'room4', 'west': 'room7', 'item': 'ob3'},
    'r4': {'name': 'Room4', 'south': 'room3', 'item': 'ob4'},
    'r5': {'name': 'Room5', 'east': 'room6', 'south': 'room7', 'item': 'ob5'},
    'r6': {'name': 'Room6', 'west': 'room5', 'item': 'ob6'},
    'r7': {'name': 'Room7', 'north': 'room5', 'east': 'room3', 'south': 'room1', 'west': 'room8', 'item': 'nothing'},
    'r8': {'name': 'Room8', 'east': 'room7', 'item': 'monster'}
}

location = rooms['r7']

command = input('You are in {}.  What would you like to do?: '.format(location['name']))#WORKS 
    #HERE
while True:
    command = input('You are in {}.  What would you like to do?: '.format(location['name']))#ERROR
    if command in location:
        location = command
        continue
    else:
        print('Invalid Input.  Please type a direction.')

Answer 1

这是您目前拥有的代码的固定版本。

rooms = {
    'room1': {'name': 'Room1', 'north': 'room7', 'east': 'room2', 'item': 'ob1'},
    'room2': {'name': 'Room2', 'west': 'room1', 'item': 'ob2'},
    'room3': {'name': 'Room3', 'north': 'room4', 'west': 'room7', 'item': 'ob3'},
    'room4': {'name': 'Room4', 'south': 'room3', 'item': 'ob4'},
    'room5': {'name': 'Room5', 'east': 'room6', 'south': 'room7', 'item': 'ob5'},
    'room6': {'name': 'Room6', 'west': 'room5', 'item': 'ob6'},
    'room7': {'name': 'Room7', 'north': 'room5', 'east': 'room3', 'south': 'room1', 'west': 'room8', 'item': 'nothing'},
    'room8': {'name': 'Room8', 'east': 'room7', 'item': 'monster'}
}

location = rooms['room7']

while True:
    command = input(
        f"You are in {location['name']}.  What would you like to do?: "
    )
    if command in location:
        location = rooms[location[command]]
    else:
        print('Invalid Input.  Please type a direction.')

while循环与问题没有任何关系。 两个主要错误是：

1. 您的rooms dict 不会始终使用房间 ID。 为了能够使用方向查找相应的房间，他们需要以相同的方式引用房间。 我已经将rooms键标准化为使用房间本身使用的roomN格式。

2. 您需要正确地将方向转换到下一个房间。 这要求您首先根据当前location和command的组合获取房间 ID，然后从rooms字典中获取下一个房间——所有这些都只是rooms[location[command]] 。

请注意，如果用户输入“名称”或“项目”作为方向，您的程序仍然会崩溃！ 我可能会通过将方向与其他房间数据分开来解决这个问题，这样您的程序就不可能将方向与房间的其他信息混淆。 例如：

from typing import Dict, List, NamedTuple


class Room(NamedTuple):
    name: str
    exits: Dict[str, str]  # map of direction to room ID
    items: List[str]


rooms = {
    'room1': Room('Room1', {'north': 'room7', 'east': 'room2'}, ['ob1']),
    'room2': Room('Room2', {'west': 'room1'}, ['ob2']),
    # etc
    'room7': Room('Room7', {'north': 'room5', 'east': 'room3', 'south': 'room1', 'west': 'room8'}, []),
    'room8': Room('Room8', {'east': 'room7'}, ['monster'])
}

location = rooms['room7']

while True:
    command = input(
        f"You are in {location.name}.  What would you like to do?: "
    )
    if command in location.exits:
        location = rooms[location.exits[command]]
    elif command == "look":
        print(f"Exits are {', '.join(location.exits.keys())}.")
        if location.items:
            print(f"There is {', '.join(location.items)} here.")
    elif command == "quit"
        print("Bye!")
        break
    else:
        print("Invalid Input.  Please type a direction.")
        print(f"Exits from this room: {', '.join(location.exits.keys())}")

You are in Room7.  What would you like to do?: south
You are in Room1.  What would you like to do?: look
Exits are north, east.
There is ob1 here.
You are in Room1.  What would you like to do?: east
You are in Room2.  What would you like to do?: look
Exits are west.
There is ob2 here.
You are in Room2.  What would you like to do?: get ob2
Invalid Input.  Please type a direction.
Exits from this room: west
You are in Room2.  What would you like to do?:

Answer 2

问题出在这一行

location = command

您将location （字典room['r7'] ）替换为变量command ，它是一个类似于"north"的字符串。

然后您再次进入 while 循环（ while True ），然后执行以下操作：

format(location['name']))

此时， location是一个字符串，在 Python 中你不能像这样对字符串进行切片。

我还不清楚你在做什么时想要达到的目标

location = command