Dump object into yaml without quotes

Question

I had some object that I want to turn into yaml, the only thing is that I need to be able to put "!anything" without quotes into it.

When I try it with pyyaml I end up with '!anything' inside my yaml file.

I've already tried using ruamel.yaml PreservedScalarString and LiteralScalarString. And it kind of works, but not in the way that I need to work. The thing is I end up with yaml that looks like this:

10.1.1.16:
            text: '1470814.27'
            confidence: |-
              !anything

But I don't need this |- symbol.

My goal is to get yaml like this:

10.1.1.16:
            text: '1470814.27'
            confidence: !anything

Any ideas how I can achieve that?

Answer 1

To dump a custom tag, you need to define a type and register a representer for that type. Here's how to do it for scalars:

import yaml

class MyTag:
  def __init__(self, content):
    self.content = content

  def __repr__(self):
    return self.content

  def __str__(self):
    return self.content

def mytag_dumper(dumper, data):
  return dumper.represent_scalar("!anything", data.content)

yaml.add_representer(MyTag, mytag_dumper)

print(yaml.dump({"10.1.1.16": {
    "text": "1470814.27",
    "confidence": MyTag("")}}))

This emits

10.1.1.16:
  confidence: !anything ''
  text: '1470814.27'

Note the '' behind the tag, which is the tagged scalar (no, you can't get rid of it). You can tag collections as well but you'll need to use represent_sequence or represent_mapping accordingly.