Convert dict to yaml with preserved quotes only for values

user_17220071 0
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I have python dict:

t1 = [{'system': 'android',
           'nice': False,
           'pass': [{'success': ['a', 'b', 'c']}],
           'warning': [{'pass': ['a', 'b', 'c']}],
           'number': 1}]

I need to get YAML like this, where only values are in quotes:

- system: 'android'
  nice: false
  pass:
    - success:
        - 'a'
        - 'b'
        - 'c'
  warning:
    - pass:
        - 'a'
        - 'b'
        - 'c'
  number: 1

What I tried:

from ruamel.yaml import YAML
import sys
from ruamel.yaml.compat import StringIO

yaml = YAML()
yaml.preserve_quotes = True
buf = StringIO()
yaml.dump(t1, buf)
yaml.indent(mapping=2, sequence=4, offset=2)
data = yaml.load(buf.getvalue())
yaml.dump(data, sys.stdout)

but yaml.preserve_quotes = True does not work and output is:

  - system: android
    nice: false
    pass:
      - success:
          - a
          - b
          - c
    warning:
      - pass:
          - a
          - b
          - c
    number: 1

What should I do?

ruamel.yaml python-3.x yaml
1 Answers

The "preserve" in preserve_quotes is to keep existing quotes when loading and then dumping using ruamel.yaml. Since what you load has not quotes, setting it has no function.

But you can load your expected output and analyse how that is loaded, which gives a clue about what to do:

import sys
import ruamel.yaml

yaml_str = """\
- system: 'android'
"""
    
yaml = ruamel.yaml.YAML()
yaml.preserve_quotes = True
data = yaml.load(yaml_str)
print(type(data[0]['system']))
yaml.dump(data, sys.stdout)

which gives:

<class 'ruamel.yaml.scalarstring.SingleQuotedScalarString'>
- system: 'android'

so the thing to do is:


import sys
import ruamel.yaml
from ruamel.yaml.scalarstring import SingleQuotedScalarString as SQ

t1 = [{'system': SQ('android'),
           'nice': False,
           'pass': [{'success': [SQ('a'), SQ('b'), SQ('c')]}],
           'warning': [{'pass': [SQ('a'), SQ('b'), SQ('c')]}],
           'number': 1}]

yaml = ruamel.yaml.YAML()
yaml.indent(mapping=2, sequence=4, offset=2)

def dedent(s):
    res = []
    count = 0
    for line in s.splitlines(True):
        if not res:
            while line[count] == ' ':
                count += 1
        res.append(line[count:])
    return ''.join(res)

yaml.dump(t1, sys.stdout, transform=dedent)

which gives what you want:

- system: 'android'
  nice: false
  pass:
    - success:
        - 'a'
        - 'b'
        - 'c'
  warning:
    - pass:
        - 'a'
        - 'b'
        - 'c'
  number: 1

However if you read this with a proper YAML parser the quotes are superfluous.

All of your indents in ruamel.yaml are the same, since you seem to want to have an offset for the sequence element indicator (-), you need to increase the sequence indent from the normal 2 to e.g. 4. But since your root collection is a sequence, this gets of course indented as well. That is why you need to post-process the output (using transform=dedent) to get the root level sequence element indicator flush with the left margin.

user_13079050
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