pyyaml and using quotes for strings only

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).

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

import sysimport ruamel.yamlyaml_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)

which outputs (including the preserved comment):

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

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).

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

Right, so borrowing heavily from this answer, you can do something like this:

import yaml# define a custom representer for stringsdef quoted_presenter(dumper, data):    return dumper.represent_scalar('tag:yaml.org,2002:str', data, style='"')yaml.add_representer(str, quoted_presenter)env_file = 'input.txt'with open(env_file) as f:    env_dict = yaml.load(f)    print yaml.dump(env_dict, default_flow_style=False)

However, this just overloads it on all strings types in the dictionary so it'll quote the keys as well, not just the values.

It prints:

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

Is this what you want? Not sure what you mean by variable names, do you mean the keys?

you can use the following method to retain your double quoted scalar object in yaml:

Taking your yaml example:

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

Loading it into an env_dict (dictionary):

myyaml = '''---my_vars:  my_env: "dev"  my_count: 3'''env_dict = yaml.load(myyaml, yaml.FullLoader) # loading yamlprint(env_dict){'my_vars': {'my_env': 'dev', 'my_count': 3}}# Define a quoted class, which uses style = '"' and add representer to yamlclass quoted(str):    passdef quoted_presenter(dumper, data):    return dumper.represent_scalar('tag:yaml.org,2002:str', data, style='"')yaml.add_representer(quoted, quoted_presenter)# Now, we update the dictionary env_dict as follows for the "dev" # value which needs to be a double quoted scalarenv_dict['my_vars'].update(my_env = quoted("dev")) # this makes "dev"# a double quoted scalar# Now, we dump the yaml as beforeyaml.dump(env_dict, sys.stdout, indent=4, default_flow_style=False, explicit_start=True)# which outputs---my_vars:    my_count: 3    my_env: "dev"

These links helped me to arrive at this answer : Any yaml libraries in Python that support dumping of long strings as block literals or folded blocks?

How can I control what scalar form PyYAML uses for my data?

Also, this one is a great article to read on To Quote or not to Quote?

Hope, this helps!