Transform Attribute In Yaml.dump Is Not Working

If we want to alter the output of yaml.dump we can use tranform keyword argument. Documentation: https://yaml.readthedocs.io/en/latest/example.html Here is the yaml data: metadata:

Solution 1:

Well I got the answer now. Have some problems with StringIO only, because YAML() always sets the encoding to utf-8 (and allow_unicode = True) Changing to use io doesn't bring anything. If you want to write to a StringIO in 2.7 you'll have to disable the utf-8 encoding:

i.e.

yaml = YAML(typ="safe")
yaml.default_flow_style = Falsestream = StringIO()
yaml.encoding = None

For more info visit this ticket : https://sourceforge.net/p/ruamel-yaml/tickets/271/