是或否在 PyYAML 中转储为 'yes' 或 'no'

Question

当使用 PyYAML 将包含值 YES、NO 的字典转储到 YAML 时，YES/NO 被引用为 'YES' 或 'NO'。我怎样才能得到不带引号的 YES 或 NO？

Answer 1

如果你想转储 YES/yes/Yes 和 NO/no/No 作为非引用标量，你必须制作一个解析器（该代码由 PyYAML 转储器和 PyYAML 加载器使用），其方式类似于防止从 YAML 将这些值作为布尔值加载。

import re
import yaml as yaml
from yaml.resolver import BaseResolver, Resolver
from yaml.emitter import Emitter
from yaml.serializer import Serializer
from yaml.representer import Representer as Repr


class MyResolver(BaseResolver):
    pass

MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:bool',
    re.compile(u'''^(?:true|True|TRUE|false|False|FALSE)$''', re.X),
    list(u'tTfF'))

MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:float',
    re.compile(u'''^(?:
     [-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+]?[0-9]+)?
    |[-+]?(?:[0-9][0-9_]*)(?:[eE][-+]?[0-9]+)
    |\.[0-9_]+(?:[eE][-+][0-9]+)?
    |[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]*
    |[-+]?\.(?:inf|Inf|INF)
    |\.(?:nan|NaN|NAN))$''', re.X),
    list(u'-+0123456789.'))

MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:int',
    re.compile(u'''^(?:[-+]?0b[0-1_]+
    |[-+]?[0-9]+
    |[-+]?0o?[0-7_]+
    |[-+]?(?:0|[1-9][0-9_]*)
    |[-+]?0x[0-9a-fA-F_]+
    |[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$''', re.X),
    list(u'-+0123456789'))

MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:merge',
    re.compile(u'^(?:<<)$'),
    [u'<'])

MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:null',
    re.compile(u'''^(?: ~
    |null|Null|NULL
    | )$''', re.X),
    [u'~', u'n', u'N', u''])

MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:timestamp',
    re.compile(u'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
    |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
    (?:[Tt]|[ \t]+)[0-9][0-9]?
    :[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)?
    (?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$''', re.X),
    list(u'0123456789'))

MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:value',
    re.compile(u'^(?:=)$'),
    [u'='])

# The following resolver is only for documentation purposes. It cannot work
# because plain scalars cannot start with '!', '&', or '*'.
MyResolver.add_implicit_resolver(
    u'tag:yaml.org,2002:yaml',
    re.compile(u'^(?:!|&|\*)$'),
    list(u'!&*'))


class MySafeDumper(Emitter, Serializer, Repr, MyResolver):
    def __init__(self, stream,
                 default_style=None, default_flow_style=None,
                 canonical=None, indent=None, width=None,
                 allow_unicode=None, line_break=None,
                 encoding=None, explicit_start=None, explicit_end=None,
                 version=None, tags=None):
        Emitter.__init__(self, stream, canonical=canonical,
                         indent=indent, width=width,
                         allow_unicode=allow_unicode, line_break=line_break)
        Serializer.__init__(self, encoding=encoding,
                            explicit_start=explicit_start,
                            explicit_end=explicit_end,
                            version=version, tags=tags)
        Repr.__init__(self, default_style=default_style,
                                 default_flow_style=default_flow_style)
        MyResolver.__init__(self)

print(yaml.dump(dict(sampe='Yes'), Dumper=MySafeDumper))

这给出：

{sampe: Yes}

正如您在评论中指出的那样。如果您也希望能够将其作为字符串加载，则应使用上面链接的答案中的构造函数代码，两个答案的解析器部分相同。

是或否在 PyYAML 中转储为 'yes' 或 'no'

yes or no dumping as 'yes' or 'no' in PyYAML

pyyaml

python-2.7