读取YAML文件和访问列表

Question

我目前正在从.yml文件中读取数据。文件中的每个主条目都有以下部分：

- !
  name: Martial Focus
  prerequisites:
    tier1:
      any:
        Attribute:
        - Attribute1:§ 1
        - Attribute2:§ 1
        Feat:
        - Feat1
        Other:
        - Other Prerequisites
  cost:
  - 3
  description: |
    [...]
  effect: |
    [...]

我已经能够读取所有的数据，包括“先决条件”，但是这里我有一个特殊的问题:对于其他数据，我能够访问子列表的地方--它似乎与此不同：

"any:“部分是可选的，所以它也可以这样说

prerequisites:
    tier1:
      Attribute:
      - Attribute1:§ 1
      - Attribute2:§ 1
      Feat:
      - Feat1
      Other:
      - Other Prerequisites

读取.yml文件可将上述部分转换为

'prerequisites': {
  'tier1': {
    'any': {
      'Attribute': ['Attribute1:§ 1', 'Attribute2:§ 1'],
      'Feat': ['Feat1'],
      'Other': ['Other Prerequisites']
    }
  }
}

因此，在我的代码中，对于每一个"tierX"，我都会检查它是否包含一个键"any:“

if 'any' in tier:
  # do the stuff to be done if 'any' exists
else:
  # do the stuff to be done if it doesn't

但这似乎从来都不是真的。因为“属性：”、“壮举：”和“其他：”也是可选的，我对if-否则语句中的那些语句也是这样做的，尽管对于那些没有其他语句的语句，它们也有相同的问题。下面你可以找到我正在使用的代码。自从我今天从蟒蛇开始的时候，它就不会是最漂亮的了，但我希望你能帮我：

        prerequisites = ""
        tierNum = 0
        for tier in data['prerequisites']:
            tierNum += 1
            thisTier = ""
            if 'any' in tier:
                print("'any' found!")
                content = tier['any']
                if 'Other' in content:
                    other = ""
                    for s2 in content['Other'][:-1]:
                        other += s2 + ", "
                    thisTier += "**" + other
                    if len(content['Other'][:-1]) == 0:
                        thisTier += str(content['Other'][-1:])
                    else:
                        thisTier += "or " + str(content['Other'][-1:])

                    if 'Attribute' in content:
                        attributes = ""
                        for s2 in content['Attribute'][:-1]:
                            attributes += s2 + ", "
                        if thisTier.length() == 0:
                            thisTier += "**" + attributes
                        else:
                            thisTier += ", or " + attributes
                        if len(content['Attribute'][:-1]) == 0:
                            thisTier += str(content['Attribute'][-1:])
                        else:
                            thisTier += "or " + str(content['Attribute'][-1:])

                    if 'Feat' in content:
                        feats = ""
                        for s2 in content['Feat'][:-1]:
                            feats += s2 + ", "
                        if thisTier.length() == 0:
                            thisTier += "**" + feats
                        else:
                            thisTier += ", or " + feats
                        if len(content['Feat'][:-1]) == 0:
                            thisTier += str(content['Feat'][-1:])
                        else:
                            thisTier += "or " + str(content['Feat'][-1:])

            else:
                content = tier
                if 'Other' in content:
                    other = ""
                    for s2 in content['Other'][:-1]:
                        other +=  s2 + ", "
                    thisTier += "**" + other
                    if len(content['Other'][:-1]) == 0:
                        thisTier += str(content['Other'][-1:])
                    else:
                        thisTier += "or " + str(content['Other'][-1:])

                if 'Attribute' in content:
                    attributes = ""
                    for s2 in content['Attribute'][:-1]:
                        attributes += s2 + ", "
                    thisTier += "**" + attributes
                    if len(content['Attribute'][:-1]) == 0:
                        thisTier += str(content['Attribute'][-1:])
                    else:
                        thisTier += "or " + str(content['Attribute'][-1:])

                if 'Feat' in content:
                    feats = ""
                    for s2 in content['Feat'][:-1]:
                        feats += s2 + ", "
                    thisTier += "**" + feats
                    if len(content['Feat'][:-1]) == 0:
                        thisTier += str(content['Feat'][-1:])
                    else:
                        thisTier += "or " + str(content['Feat'][-1:])

            prerequisites += "*Tier {0}:\n{1}\n".format(tierNum, thisTier)
        prerequisites = prerequisites[:-1]

我正在做一些像content['Feat'][:-1]这样的事情，以便获得除了最后一个元素之外的所有元素，这样我就可以在最后一个元素前面添加一个", or "，如果有多个元素的话。

编辑：我想要的输出应该如下所示：

Prerequisites:
*Tier 1:
**Attribute1 1, or Attribute2 1
**Feat1
**Other Prerequisites

如果没有的话

Prerequisites:
*Tier 1:
**Attribute1 1, or Attribute2 1, or Feat1, or Other Prerequisites

如果没有

Answer 1

您的问题是for tier in data["predicates"]在谓词字典的键上迭代，因此后续if "any" in tier实际上计算了"any" in "tier1"，这是导致始终为false的原因。

您想在这里测试的是"any" in data["predicates"]["tier1"]。在使用字典(即映射)时，您必须区分key及其对应的value。

有趣的是，你已经为下一关做好了准备：

# ...
content = tier['any']
if 'Other' in content:
    other = ""
    for s2 in content['Other']:
       # ...

遍历字典的方法

d = {"key1":"value1", "key2":"value2", "key3":"value3"}
for key in d:
  print(key)
# prints key1, key2, key3
for key in d.keys():
  print(key)
# prints key1, key2, key3
for value in d.values():
  print(value)
# prints value1, value2, value3
for item in d.items():
  print(item)
# prints (key1,value1), (key2,value2), (key3,value3)
for key, value in d.items():
  print(key)
  print(value)
# prints key1, value1, key2, value2, key3, value3

参见python文档这里和这里

由于您是Python新手，不知道什么是可能的，请允许我为您提供一个更优雅的解决方案，不需要所有重复的字符串操作：

import yaml


yamldata1 = r"""
- !
  name: Martial Focus
  prerequisites:
    tier1:
      any:
        Attribute:
        - Attribute1:§ 1
        - Attribute2:§ 1
        Feat:
        - Feat1
        Other:
        - Other Prerequisites
  cost:
  - 3
  description: |
    [...]
  effect: |
    [...]
"""
yamldata2 = r"""
- !
  name: Martial Focus
  prerequisites:
    tier1:
        Attribute:
        - Attribute1:§ 1
        - Attribute2:§ 1
        Feat:
        - Feat1
        Other:
        - Other Prerequisites
  cost:
  - 3
  description: |
    [...]
  effect: |
    [...]
"""


def process(data):
    output = ""
    for tier_name, tier in data['prerequisites'].items():
        output += f"* {tier_name}"
        if 'any' in tier:
            content = tier['any']
            prerequisites = content.get('Other', []) + content.get('Attribute', []) + content.get('Feat', [])
            if prerequisites:
                output += "\n** " + " or ".join(prerequisites)
        else:
            content = tier
            prerequisites = [content.get('Other', []), content.get('Attribute', []), content.get('Feat', [])]

            for subset in prerequisites:
                if subset:
                    output += "\n** " + " or ".join(subset)
    return output


data = yaml.load(yamldata1)[0]
print(process(data))
print('#'*10)
data = yaml.load(yamldata2)[0]
print(process(data))