PyYAML和组合，属性

Question

我一直在努力掌握PyYAML，因为我喜欢它的可读性，并且希望在一些开源项目中使用它作为JSON的替代品。在

然而，我正在努力理解如何用组合构造对象。我打开了这个问题：PyYAML - how to deal with compositon它似乎在读出信息方面有效，但在整个程序的上下文中却不行。在

这里有一个简单的例子来说明我想要表达的意思：

import yaml
import data

class DungeonObject(yaml.YAMLObject):
    yaml_tag = u'!DungeonObject'
    def __init__(self, x, y, char, name, blocks=False, fighter=None):
        self.x = x
        self.y = y
        self.char = char
        self.name = name
        self.blocks = blocks

        self.fighter = fighter
        if self.fighter:
            self.fighter.owner = self


    def __repr__(self):
        return "%s(x=%r, y=%r, char=%r, name=%r, blocks=%r fighter=%r)" % (self.__class__.__name__, self.x, self.y, self.char, self.name, self.blocks, self.fighter)

class Fighter(yaml.YAMLObject):
    yaml_tag = u'!Fighter'
    #combat-related properties and methods (monster, player, NPC).
    def __init__(self, hp, defense, strength):
        self.hp = hp
        self.base_defense = defense
        self.base_strength = strength
    def __repr__(self):
        return "%s(hp=%r, defense=%r, strength=%r)" % (self.__class__.__name__, self.hp, self.defense, self.strength)


monsters = {DungeonObject.name : DungeonObject for DungeonObject in yaml.load_all(data.monsterdata)}
print (monsters)

还有我的YAML文件：

^{pr2}$

有了这个，我得到了一个错误： 第32行，英寸 怪物={地下对象.name：中的DungeonObject的DungeonObject全部加载(数据怪兽数据)} AttributeError:“Fighter”对象没有属性“name”

Answer 1

每个文档都应该包含一个由Fighter和DungeonObject组成的序列/列表。前者没有名字，所以你应该过滤那些实际上是DungeonObject类型而不是Fighter类型的DungeonObject。在

有点令人困惑的是，您还使用了一个变量DungeonObject，因此请尝试使用dungeon_object作为变量：

from ruamel import yaml

monsterdata = """
 -
- !Fighter &fighter_component
    hp: 20
    defense: 0
    strength: 4
- !DungeonObject
    x: x
    y: y
    char: 'o'
    name: 'orc'
    blocks: True
    fighter: fighter_component
 -
- !Fighter &fighter_component
    hp: 9
    defense: 0
    strength: 10
- !DungeonObject
    x: x
    y: y
    char: 't'
    name: 'troll'
    blocks: True
    fighter: fighter_component
"""


class DungeonObject(yaml.YAMLObject):
    yaml_tag = u'!DungeonObject'

    def __init__(self, x, y, char, name, blocks=False, fighter=None):
        self.x = x
        self.y = y
        self.char = char
        self.name = name
        self.blocks = blocks

        self.fighter = fighter
        if self.fighter:
            self.fighter.owner = self

    def __repr__(self):
        return "{}(x={!r}, y={!r}, char={!r}, name={!r}, blocks={!r} fighter={!r})".format(
            self.__class__.__name__, self.x, self.y, self.char, self.name,
            self.blocks, self.fighter)


class Fighter(yaml.YAMLObject):
    yaml_tag = u'!Fighter'
    # combat-related properties and methods (monster, player, NPC).

    def __init__(self, hp, defense, strength):
        self.hp = hp
        self.base_defense = defense
        self.base_strength = strength

    def __repr__(self):
        return "{}(hp={!r}, defense={!r}, strength={!r})".format(
            self.__class__.__name__, self.hp, self.defense, self.strength)

monsters = {}
for doc in yaml.load_all(monsterdata, Loader=yaml.Loader):
    for dungeon_object in doc:
        if isinstance(dungeon_object, DungeonObject):
            monsters[dungeon_object.name] = dungeon_object

print (monsters)

它给出了：

^{pr2}$

我更新了__repr__以使用更现代的.format()方法。因为我正在使用拉梅尔亚姆勒（这是PyYAML功能的超集，并且向后兼容），我需要显式地指定加载程序，以消除使用默认加载程序时load_all不安全的警告。（免责声明：我是该软件包的开发者）