python - LPTHW Ex47 属性错误

Question

我正在处理 LPTHW，但遇到了 Ex47 的属性错误。我浏览过这个网站并在谷歌上搜索帮助，但似乎找不到任何东西。

我得到的错误是这样的:

  Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/Users/Donatron/temp/My Python Stuff/projects/ex47/tests/ex47_tests.py", line 26, in test_map
    start.add_paths({'west': west, 'down': down})
  File "/Users/Donatron/temp/My Python Stuff/projects/ex47/ex47/game.py", line 12, in add_paths
    self.paths.update(paths)
AttributeError: 'list' object has no attribute 'update'

我的“游戏”代码如下所示:-

class Room(object):


    def __init__(self, name, description):
        self.name = name
        self.description = description
        self.paths = []

    def go(self, direction):
        return self.paths.get(direction, None)

    def add_paths(self, paths):
        self.paths.update(paths)

我的“测试”代码如下所示:-

from nose.tools import *
from ex47.game import Room

def test_room():
    gold = Room("GoldRoom",
                """This room has gold in it you can grab. There's a
                door to the north.""")
    assert_equal(gold.name, "GoldRoom")
    assert_equal(gold.paths, [])

def test_room_paths():
    center = Room("Center", "Test room in the center.")
    north = Room("North", "Test room in the north.")
    south = Room("South", "Test room in the south.")

    center.add_paths({'north': north, 'south': south})
    assert_equal(center.go('north'), north)
    assert_equal(center.go('south'), south)

def test_map():
    start = Room("Start", "You can go west and down a hole.")
    west = Room("Trees", "There are trees here, you can go east.")
    down = Room("Dungeon", "It's dark down here, you can go up.")

    start.add_paths({'west': west, 'down': down})
    west.add_paths({'east': start})
    down.add_paths({'up': start})

    assert_equal(start.go('west'), west)
    assert_equal(start.go('west').go('east'), start)
    assert_equal(start.go('down').go('up'), start)

这让我很头疼!我哪里出错了？

提前感谢您的帮助:-)

Answer 1

self.paths应该是dict {}不是列表

self.paths = {}

dicts有get和update方法，你的self.paths是一个列表[]它没有更新方法，这就是您收到错误的原因。

在错误中您可以看到 start.add_paths({'west': west, 'down': down})它正在添加一个传递给 self.paths 的字典它试图调用 self.paths.update方法但失败为 self.paths设置为list而不是dict {} .

return self.paths.get(direction, None) # 使用dict.get方法

self.paths.update(paths) # 使用dict.update方法。

dict.get(direction, None)返回None默认情况下，如果 key dict 中不存在，您可以指定任何默认返回值来代替 None 。