如何从同一个YAML文件的其他地方引用YAML“设置”?

我有以下YAML:

paths:
  patha: /path/to/root/a
  pathb: /path/to/root/b
  pathc: /path/to/root/c

我如何“正常化”它，通过从三个路径中删除/path/到/root/，并将其作为自己的设置，类似于:

paths:
  root: /path/to/root/
  patha: *root* + a
  pathb: *root* + b
  pathc: *root* + c

显然这是无效的，我瞎编的。真正的语法是什么?这能做到吗?

当前回答

使用OmegaConf

OmegaConf是一个基于yaml的分层配置系统，在变量插值功能下支持此功能。使用OmegaConf v2.2.2:

创建YAML文件路径。Yaml如下:

paths:
  root: /path/to/root/
  patha: ${.root}a
  pathb: ${.root}b
  pathc: ${.root}c

然后我们可以读取可变路径的文件:

from omegaconf import OmegaConf
conf = OmegaConf.load("test_paths.yaml")

>>> conf.paths.root
'/path/to/root/'

>>> conf.paths.patha
'/path/to/root/a'
>>> conf.paths.pathb
'/path/to/root/b'
>>> conf.paths.pathc
'/path/to/root/c'

深度和交叉裁判

可以定义更复杂的(嵌套的)结构，使用变量的相对深度来引用其他变量:

创建另一个文件nested_paths.yaml:

data:
    base: data
    sub_dir_A:
        name: a
        # here we note that `base` is two levels above this variable
        # hence we will use `..base` two dots but the `name` variable is
        # at the same level hence a single dot `.name`
        nested_dir: ${..base}/sub_dir/${.name}/last_dir 
    sub_dir_B:
        # add another level of depth
        - name: b
          # due to another level of depth, we have to use three dots
          # to access `base` variable as `...base`
          nested_file: ${...base}/sub_dir/${.name}/dirs.txt
        - name: c
          # we can also make cross-references to other variables
          cross_ref_dir: ${...sub_dir_A.nested_dir}/${.name}

我们可以再次检查:

conf = OmegaConf.load("nested_paths.yaml")

# 1-level of depth reference
>>> conf.data.sub_dir_A.nested_dir
'data/sub_dir/a/last_dir'

# 2-levels of depth reference
>>> conf.data.sub_dir_B[0].nested_file
'data/sub_dir/b/dirs.txt'

# cross-reference example
>>> conf.data.sub_dir_B[1].cross_ref_dir
'data/sub_dir/a/last_dir/c'

在无效引用的情况下(例如错误的深度，错误的变量名)，OmegaConf将抛出错误OmegaConf .errors. interpolationresolutionerror。在Hydra中，它还用于配置复杂的应用程序。

2022-07-18 15:16:27

其他回答

我已经创建了一个库，在Packagist上可用，执行这个函数: https://packagist.org/packages/grasmash/yaml-expander

YAML文件示例:

type: book
book:
  title: Dune
  author: Frank Herbert
  copyright: ${book.author} 1965
  protaganist: ${characters.0.name}
  media:
    - hardcover
characters:
  - name: Paul Atreides
    occupation: Kwisatz Haderach
    aliases:
      - Usul
      - Muad'Dib
      - The Preacher
  - name: Duncan Idaho
    occupation: Swordmaster
summary: ${book.title} by ${book.author}
product-name: ${${type}.title}

例子逻辑:

// Parse a yaml string directly, expanding internal property references.
$yaml_string = file_get_contents("dune.yml");
$expanded = \Grasmash\YamlExpander\Expander::parse($yaml_string);
print_r($expanded);

结果数组:

array (
  'type' => 'book',
  'book' => 
  array (
    'title' => 'Dune',
    'author' => 'Frank Herbert',
    'copyright' => 'Frank Herbert 1965',
    'protaganist' => 'Paul Atreides',
    'media' => 
    array (
      0 => 'hardcover',
    ),
  ),
  'characters' => 
  array (
    0 => 
    array (
      'name' => 'Paul Atreides',
      'occupation' => 'Kwisatz Haderach',
      'aliases' => 
      array (
        0 => 'Usul',
        1 => 'Muad\'Dib',
        2 => 'The Preacher',
      ),
    ),
    1 => 
    array (
      'name' => 'Duncan Idaho',
      'occupation' => 'Swordmaster',
    ),
  ),
  'summary' => 'Dune by Frank Herbert',
);

2017-01-13 02:36:50

YML定义:

dir:
  default: /home/data/in/
  proj1: ${dir.default}p1
  proj2: ${dir.default}p2
  proj3: ${dir.default}p3

在百里叶的某个地方

<p th:utext='${@environment.getProperty("dir.default")}' />
<p th:utext='${@environment.getProperty("dir.proj1")}' />

输出: / home /数据/ in / / home /数据/ in / p1

2017-10-02 12:49:44

在某些语言中，你可以使用替代库，例如，tampax是YAML处理变量的实现:

const tampax = require('tampax');

const yamlString = `
dude:
  name: Arthur
weapon:
  favorite: Excalibur
  useless: knife
sentence: "{{dude.name}} use {{weapon.favorite}}. The goal is {{goal}}."`;

const r = tampax.yamlParseString(yamlString, { goal: 'to kill Mordred' });
console.log(r.sentence);

// output : "Arthur use Excalibur. The goal is to kill Mordred."

编者注:海报作者也是本包的作者。

2017-11-01 16:35:13

另一种方法是简单地使用另一个字段。

paths:
  root_path: &root
     val: /path/to/root/
  patha: &a
    root_path: *root
    rel_path: a
  pathb: &b
    root_path: *root
    rel_path: b
  pathc: &c
    root_path: *root
    rel_path: c

2014-11-01 14:28:46