我可以在 ruamel.yaml 的 CommentedMap 中插入一行吗？

Question

我知道这与 this SO question 有关，但我最关心的是这是否会影响保留评论等内容。

import ruamel.yaml as yaml

yaml_str = """\
first_name: Art
occupation: Architect  # This is an occupation comment
about: Art Vandelay is a fictional character that George invents...
"""

data = yaml.load(yaml_str, Loader=yaml.RoundTripLoader)

# I'd like to extend CommentedMap so that I can do something like:
data.insert(1, 'last_name', 'Vandelay')

print(yaml.dump(data, Dumper=yaml.RoundTripDumper))

应该输出：

first_name: Art
last_name: Vandelay
occupation: Architect  # This is an occupation comment
about: Art Vandelay is a fictional character that George invents...

应该不输出：

first_name: Art
last_name: Vandelay    # This is an occupation comment
occupation: Architect
about: Art Vandelay is a fictional character that George invents...

Answer 1

在 Python 2.7 和 Python 3.X 上至少 ruamel.yaml 0.11.11，这工作正常：

import ruamel.yaml

yaml_str = """\
first_name: Art
occupation: Architect  # This is an occupation comment
about: Art Vandelay is a fictional character that George invents...
"""

data = ruamel.yaml.round_trip_load(yaml_str)
data.insert(1, 'last name', 'Vandelay')

print(ruamel.yaml.round_trip_dump(data))

给出：

first_name: Art
last name: Vandelay
occupation: Architect  # This is an occupation comment
about: Art Vandelay is a fictional character that George invents...

因为行尾注释与 CommentedMap 中的行键相关联。（Python 2.7.11 在 Linux Mint 上 ruamel.yaml 0.11.10。）

这不适用于带有 Python3 的 ruamel.yaml 的旧版本，因为您正在使用的 .insert() 是成熟的 ruamel.ordereddict 的一个功能，并且标准库中的 OrderedDict 没有那个方法。因此，您需要将 .insert() 函数移植到 CommentedMap:

import ruamel.yaml
from ruamel.yaml.comments import CommentedMap
from ruamel.yaml.compat import ordereddict

yaml_str = """\
first_name: Art
occupation: Architect  # This is an occupation comment
about: Art Vandelay is a fictional character that George invents...
"""

def com_insert(self, pos, key, value, comment=None):
    od = ordereddict()
    od.update(self)
    for k in od:
        del self[k]
    for index, old_key in enumerate(od):
        if pos == index:
            self[key] = value
        self[old_key] = od[old_key]
    if comment is not None:
        self.yaml_add_eol_comment(comment, key=key)

CommentedMap.insert = com_insert

data = ruamel.yaml.round_trip_load(yaml_str)
data.insert(1, 'last name', 'Vandelay', comment="new key")

print(ruamel.yaml.round_trip_dump(data))

Python3:

first_name: Art
last name: Vandelay    # new key
occupation: Architect  # This is an occupation comment
about: Art Vandelay is a fictional character that George invents...

请注意 insert() 有一个可选参数，允许您为新插入的键值对指定注释。上面的工作是因为从 CommentedMap 中删除一个键不会删除与该键关联的注释。所以我暂时把旧的键值对放在od 删除所有键值，然后将它们复制回去并在适当的时候插入新内容

以上insert，带注释，已在ruamel.yaml 0.11.11中添加 Python 2 和 3

.round_trip_load()相当于.load(...., Loader=ruamel.yaml.RoundTripLoader, ...)，.round_trip_dump()相当于`.dump(....., Dumper=ruamel.yaml.RoundTripDumper, allow_unicode=正确，...)

我可以在 ruamel.yaml 的 CommentedMap 中插入一行吗？

Can I insert a line into ruamel.yaml's CommentedMap?

python

yaml

ordereddictionary

ruamel.yaml