如何在python3中使用yaml转储保留格式

Question

我只想使用 python 更改以下 yaml 文件中的属性 anotherName。

test.yaml：

---
kind: test
scope: not far
spec:
  test1:
    options:
      - name: test.com
        anotherName: example.com
        empty: []
    groupOne: []
    emptyList:
      firstList: []
      secondList: []

代码（基于这个答案）

import yaml
with open("test.yaml", 'r') as stream:
    try:
        loaded=yaml.safe_load(stream)
    except yaml.YAMLError as exc:
        print(exc)
    temp= loaded['spec']['test1']['options']
    for elem in temp:
        elem['anotherName']='somethingChanged'
with open("modified.yaml", 'w') as stream:
    try:
        yaml.dump(loaded, stream)
        print(loaded)
    except yaml.YAMLError as exc:
        print(exc)

值已更改，但代码更改了modified.yaml<的顺序和结构< /强>：

#First it misses the thre dashes
kind: test
scope: not far
spec:
  test1:
    emptyList:
      firstList: []
      secondList: []
    groupOne: []
    options:
    - anotherName: somethingChanged #then the order is changed
      empty: []
      name: test.com

Answer 1

如果您的 PyYAML 版本高于 5.1，您可以使用 sort_keys 参数来保留顺序。唯一需要更改的行是这一行：

yaml.dump(loaded, stream, sort_keys=False)

Answer 2

你可能无法强制 pyyaml 输出特定的输出，但如果你有这样一个特定的要求，你想用什么来替代，那么为什么还要额外麻烦地解析 yml fromat 呢。将文件读入字符串然后进行替换怎么样：

import re
# Here you would need to read the file content. I define it here
content="""
---
kind: test
scope: not far
spec:
  test1:
    options:
      - name: test.com
        anotherName: example.com
        empty: []
    groupOne: []
    emptyList:
      firstList: []
      secondList: []
"""
print(re.sub(r'anotherName: [^\n]*', 'anotherName: somethingChanged', content))

输出：

---
kind: test
scope: not far
spec:
  test1:
    options:
      - name: test.com
        anotherName: somethingChanged
        empty: []
    groupOne: []
    emptyList:
      firstList: []
      secondList: []