Python之ruamel.yaml模块详解（一）

pip install -U pip setuptools wheel

pip install ruamel.yaml

C:\Users\Administrator>pip install ruamel.yaml
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple
Collecting ruamel.yaml
  Downloading https://pypi.tuna.tsinghua.edu.cn/packages/9e/cb/938214ac358fbef7058343b3765c79a1b7ed0c366f7f992ce7ff38335652/ruamel.yaml-0.17.21-py3-none-any.whl (109 kB)
     --------------------------------------- 109.5/109.5 kB 2.1 MB/s eta 0:00:00

Collecting ruamel.yaml.clib>=0.2.6
  Downloading https://pypi.tuna.tsinghua.edu.cn/packages/da/f4/928e950925fe1b9eb048ddab8eef073a52e9ae01afd06f98f1daf743e355/ruamel.yaml.clib-0.2.7-cp37-cp37m-win_amd64.whl (115 kB)
     ------------------------------------- 115.9/115.9 kB 357.0 kB/s eta 0:00:00

Installing collected packages: ruamel.yaml.clib, ruamel.yaml
Successfully installed ruamel.yaml-0.17.21 ruamel.yaml.clib-0.2.7

pip install ruamel.yaml[jinja2]

pip install ruamel.yaml.cmd

from ruamel.yaml import YAML

yaml=YAML(typ='safe')   
yaml.load(doc)

class YAML:
    def __init__(self, *, typ=None, pure=False, output=None, plug_ins=None):  # input=None,
        # type: (Any, Optional[Text], Any, Any, Any) -> None
        """
        typ: 'rt'/None -> RoundTripLoader/RoundTripDumper,  (default)
             'safe'    -> SafeLoader/SafeDumper,
             'unsafe'  -> normal/unsafe Loader/Dumper
             'base'    -> baseloader
        pure: if True only use Python modules
        input/output: needed to work as context manager
        plug_ins: a list of plug-in files
        """

    def load(self, stream):
        # type: (Union[Path, StreamTextType]) -> Any
        """
        at this point you either have the non-pure Parser (which has its own reader and
        scanner) or you have the pure Parser.
        If the pure Parser is set, then set the Reader and Scanner, if not already set.
        If either the Scanner or Reader are set, you cannot use the non-pure Parser,
            so reset it to the pure parser and set the Reader resp. Scanner if necessary
        """
        if not hasattr(stream, 'read') and hasattr(stream, 'open'):
            # pathlib.Path() instance
            with stream.open('rb') as fp:
                return self.load(fp)
        constructor, parser = self.get_constructor_parser(stream)
        try:
            return constructor.get_single_data()
        finally:
            parser.dispose()
            try:
                self._reader.reset_reader()
            except AttributeError:
                pass
            try:
                self._scanner.reset_scanner()
            except AttributeError:
                pass

from ruamel.yaml import YAML

yaml=YAML()
yaml.default_flow_style = False
yaml.dump({'a': [1, 2]}, s)

def tr(s):
    return s.replace('\n', '<\n')  # such output is not valid YAML!

yaml.dump(data, sys.stdout, transform=tr)

 def dump(self, data, stream=None, *, transform=None):
        # type: (Any, Union[Path, StreamType], Any, Any) -> Any
        if self._context_manager:
            if not self._output:
                raise TypeError('Missing output stream while dumping from context manager')
            if transform is not None:
                raise TypeError(
                    '{}.dump() in the context manager cannot have transform keyword '
                    ''.format(self.__class__.__name__)
                )
            self._context_manager.dump(data)
        else:  # old style
            if stream is None:
                raise TypeError('Need a stream argument when not dumping from context manager')
            return self.dump_all([data], stream, transform=transform)

from ruamel.yaml import YAML

yaml=YAML(typ="safe")
yaml.load("""a:\n  b: 2\n  c: 3\n""")

from ruamel.yaml import YAML

yaml=YAML(typ="safe", pure=True)
yaml.load("""a:\n  b: 2\n  c: 3\n""")