How can I delete single quotes using ruamel.yaml.dump

I wanted to make a yaml file from a python dict. But when I convert a regex string, the single quotes appears.

I want:

quickSearch:
        type: string
        maxLength: 250
        pattern: [a-zA-Z0-9.\-_\u4e00-\u9fa5]+

but the result looks like:

quickSearch:
        type: string
        maxLength: 250
        pattern: '[a-zA-Z0-9.\-_\u4e00-\u9fa5]+'

this is my code:

from ruamel.yaml import YAML
yaml = YAML()
param_dict = {
            "quickSearch": {
                "type": "string",
                "maxLength": 250,
                "pattern": "",
            }
        }
pattern = "[a-zA-Z0-9.\-_\\u4e00-\\u9fa5]+"
param_dict["quickSearch"]["pattern"] = pattern
with open("config.yaml", 'w', encoding='utf-8-sig') as f:
    yaml.dump(param_dict, f)

How to represent all string without single quotes.

In YAML you cannot represent all possible strings without quotes, I am not sure where you get that misconceptions.

The opening square bracket is a special character denoting the beginning of a flow-style sequence ( i.e. one of the two possible representations of a Python list in YAML).

Since your strings starts with a square bracket, if it would be dumped without it, it would not load back correctly, or in this case cause a loading error.

You should not worry about the quotes, any valid YAML parser will just remove them when loading back the string.