在ruamel.yaml中保持评论

Question

我正在尝试使用ruamel.yaml来操纵一些YAML文件，特别是删除特定的密钥。这似乎有效，但是在此过程中，所有遵循键的评论行和空线（直到下一个键）也将被删除。最小示例：

from ruamel.yaml import YAML
import sys


yaml_str = """\
# Our app configuration

# foo is our main variable
foo: bar

# foz is also important
foz: quz

# And finally we have our optional configs.
# These are not really mandatory, they can be
# considere as "would be nice".
opt1: foqz
"""


yaml = YAML(typ='rt')
data = yaml.load(yaml_str)

data.pop('foz', None)

yaml.dump(data, sys.stdout)

哪个给出：

# Our app configuration

# foo is our main variable
foo: bar

# foz is also important
opt1: foqz

是否有一种避免这种情况并仅删除密钥本身以及任何内联评论的方法？

Answer 1

ruamel.yaml 文档状态

除非您严重改变，否则这种保存通常不会破裂
组件的结构（删除键中的键，删除列表条目）。

因此，这种行为不应该令人惊讶。

你能做的是
在您删除密钥之前的关键上，将评论扩展到密钥上的评论
您将删除（实际上可以这样做，因为评论是
仍然在那里，在倾倒将其关联时不再有钥匙）。

import sys
import ruamel.yaml

yaml_str = """\
# Our app configuration

# foo is our main variable
foo: bar

# foz is also important
foz: quz

# And finally we have our optional configs.
# These are not really mandatory, they can be
# considere as "would be nice".
opt1: foqz
"""

undefined = object()

def my_pop(self, key, default=undefined):
    if key not in self:
        if default is undefined:
            raise KeyError(key)
        return default
    keys = list(self.keys())
    idx = keys.index(key)
    if key in self.ca.items:
        if idx == 0:
            raise NotImplementedError('cannot handle moving comment when popping the first key', key)
        prev = keys[idx-1]
        # print('prev', prev, self.ca)
        comment = self.ca.items.pop(key)[2]
        if prev in self.ca.items:
            self.ca.items[prev][2].value += comment.value
        else:
            self.ca.items[prev] = self.ca.items.pop(key)
    res = self.__getitem__(key)
    self.__delitem__(key)
    return res

ruamel.yaml.comments.CommentedMap.pop = my_pop
    
yaml = ruamel.yaml.YAML()
data = yaml.load(yaml_str)

data.pop('foz', None)

yaml.dump(data, sys.stdout)

这给出了：

# Our app configuration

# foo is our main variable
foo: bar

# foz is also important


# And finally we have our optional configs.
# These are not really mandatory, they can be
# considere as "would be nice".
opt1: foqz

如果您需要能够在评论的地图中弹出第一个键，则需要检查self.ca
并处理其注释属性，这更复杂。

与往常一样，当使用此类内部设备时，您应该固定正在使用的Ruamel.yaml版本。
这些内部将会改变。