pyyaml 并仅对字符串使用引号

问题描述

我有以下 YAML 文件:

I have the following YAML file:

---
my_vars:
  my_env: "dev"
  my_count: 3

当我用 PyYAML 读取它并再次转储时，我得到以下输出:

When I read it with PyYAML and dump it again, I get the following output:

---
my_vars:
  my_env: dev
  my_count: 3

有问题的代码:

with open(env_file) as f:
    env_dict = yaml.load(f)
    print(yaml.dump(env_dict, indent=4, default_flow_style=False, explicit_start=True))

我尝试使用 default_style 参数:

with open(env_file) as f:
    env_dict = yaml.load(f)
    print(yaml.dump(env_dict, indent=4, default_flow_style=False, explicit_start=True, default_style='"'))

但现在我明白了:

---
"my_vars":
  "my_env": "dev"
  "my_count": !!int "3"

我需要做什么来保持原始格式，对 YAML 文件中的变量名称做任何假设?

What do I need to do to keep the original formatting, without making any assumptions about the variable names in the YAML file?

推荐答案

我建议您更新为使用 YAML 1.2(2009 年发布)和向后兼容的 ruamel.yaml 包，而不是使用实现大部分 YAML 1.1 (2005) 的 PyYAML.(免责声明:我是该软件包的作者).

I suggest you update to using YAML 1.2 (released in 2009) with the backwards compatible ruamel.yaml package instead of using PyYAML which implements most of YAML 1.1 (2005). (Disclaimer: I am the author of that package).

然后您只需在加载以往返 YAML 文件时指定 preserve_quotes=True:

Then you just specify preserve_quotes=True when loading for round-tripping the YAML file:

import sys
import ruamel.yaml

yaml_str = """\
---
my_vars:
  my_env: "dev"    # keep "dev" quoted
  my_count: 3
"""

data = ruamel.yaml.round_trip_load(yaml_str, preserve_quotes=True)
ruamel.yaml.round_trip_dump(data, sys.stdout, explicit_start=True)

输出(包括保留的评论):

which outputs (including the preserved comment):

---
my_vars:
  my_env: "dev"    # keep "dev" quoted
  my_count: 3

加载字符串后，标量将成为字符串的子类，以便能够容纳引用信息，但对于所有其他目的，它将像普通字符串一样工作.如果你想替换这样的字符串(dev 到 fgw)您必须将字符串转换为该子类(ruamel.yaml.scalarstring 中的 DoubleQuotedScalarString).

After loading the string scalars will be a subclass of string, to be able to accommodate the quoting info, but will work like a normal string for all other purposes. If you want to replace such a string though (dev to fgw)you have to cast the string to this subclass ( DoubleQuotedScalarString from ruamel.yaml.scalarstring).

当往返 ruamel.yaml 默认保留键的顺序(通过插入).

When round-tripping ruamel.yaml by default preserves the order (by insertion) of the keys.

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