使用 PyYAML.dump() 生成锚点? [英] Generating anchors with PyYAML.dump()?

问题描述

我希望能够在 PyYAML 的 dump() 函数生成的 YAML 中生成锚点.有没有办法做到这一点?理想情况下，锚点应与 YAML 节点同名.

示例:

导入yamlyaml.dump({'a': [1,2,3]})'a: [1, 2, 3]\n'

我希望能够做的是生成 YAML，例如:

导入yamlyaml.dump({'a': [1,2,3]})'a: &a [1, 2, 3]\n'

我可以编写自定义发射器或转储器来执行此操作吗?还有别的方法吗?

解决方案

默认情况下，只有在检测到对先前看到的对象的引用时才会发出锚点:

<预><代码>>>>导入 yaml>>>>>>foo = {'a': [1,2,3]}>>>文档 = (foo,foo)>>>>>>打印 yaml.safe_dump(doc, default_flow_style=False)- &id001A:- 1- 2- 3- *id001

如果您想覆盖它的命名方式，您必须自定义 Dumper 类，特别是 generate_anchor() 函数.ANCHOR_TEMPLATE 也可能有用.

在您的示例中，节点名称很简单，但您需要考虑 YAML 值的多种可能性，即它可能是一个序列而不是单个值:

<预><代码>>>>导入 yaml>>>>>>foo = {('a', 'b', 'c'): [1,2,3]}>>>文档 = (foo,foo)>>>>>>打印 yaml.dump(doc, default_flow_style=False)!!蟒蛇/元组- &id001?!!蟒蛇/元组- 一种- 乙- C: - 1- 2- 3- *id001

I'd like to be able to generate anchors in the YAML generated by PyYAML's dump() function. Is there a way to do this? Ideally the anchors would have the same name as the YAML nodes.

Example:

import yaml
yaml.dump({'a': [1,2,3]})
'a: [1, 2, 3]\n'

What I'd like to be able to do is generate YAML like:

import yaml
yaml.dump({'a': [1,2,3]})
'a: &a [1, 2, 3]\n'

Can I write a custom emitter or dumper to do this? Is there another way?

解决方案

By default, anchors are only emitted when it detects a reference to an object previously seen:

>>> import yaml
>>>
>>> foo = {'a': [1,2,3]}
>>> doc = (foo,foo)
>>>
>>> print yaml.safe_dump(doc, default_flow_style=False)
- &id001
  a:
  - 1
  - 2
  - 3
- *id001

If you want to override how it is named, you'll have to customize the Dumper class, specifically the generate_anchor() function. ANCHOR_TEMPLATE may also be useful.

In your example, the node name is simple, but you need to take into account the many possibilities for YAML values, ie it could be a sequence rather than a single value:

>>> import yaml
>>>
>>> foo = {('a', 'b', 'c'): [1,2,3]}
>>> doc = (foo,foo)
>>>
>>> print yaml.dump(doc, default_flow_style=False)
!!python/tuple
- &id001
  ? !!python/tuple
  - a
  - b
  - c
  : - 1
    - 2
    - 3
- *id001

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