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。文件中包含每个主要条目的以下部分：

- !
  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数据，包括“先决条件”，但这里我有一个特殊问题： 在使用其他数据时，我能够访问子列表，这似乎有所不同：

“any:”部分是可选的，所以它也可以说类似

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

读取 .yml 文件将上面的部分转换为

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

所以在我的代码中，对于每个“tierX”，我检查它是否包含一个键“any:”通过

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。由于“Attribute：”、“Feat：”和“Other：”也是可选的，所以我对 if-else-statement 中的那些也做同样的事情，尽管对于那些没有 else-statement 的问题，它们也是同样的问题。 您可以在下面找到我正在使用的代码。自从我今天开始使用 python 以来，它不会是最漂亮的，但我希望你能帮助我：

        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]

我正在做类似content['Feat'][:-1] 之类的操作，以便获取除最后一个元素之外的所有元素，因此如果有多个元素，我可以在最后一个元素前添加", or "。

编辑： 我想要的输出是这样的：

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

如果不存在并且

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"] 遍历谓词字典的 keys，因此后续的 if "any" in tier 实际上评估 "any" in "tier1" 这总是错误的原因。

---

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

有趣的是，您已经为下一个级别做好了准备：

# ...
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

---

请参阅 python 文档 here 和 here

---

由于您是 Python 新手并且不知道什么是可能的，请允许我向您展示一个更优雅的解决方案，无需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))