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在Python中,如何将YAML映射加载为OrderedDicts?

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在Python中,如何将YAML映射加载为OrderedDicts?

注意 :有一个基于以下答案的库,该库还实现了CLoader和CDumpers:Phynix /
yamlloader

我非常怀疑这是最好的方法,但这是我想出的方法,并且确实有效。也可作为要点。

import yamlimport yaml.constructortry:    # included in standard lib from Python 2.7    from collections import OrderedDictexcept importError:    # try importing the backported drop-in replacement    # it's available on PyPI    from ordereddict import OrderedDictclass OrderedDictYAMLLoader(yaml.Loader):    """    A YAML loader that loads mappings into ordered dictionaries.    """    def __init__(self, *args, **kwargs):        yaml.Loader.__init__(self, *args, **kwargs)        self.add_constructor(u'tag:yaml.org,2002:map', type(self).construct_yaml_map)        self.add_constructor(u'tag:yaml.org,2002:omap', type(self).construct_yaml_map)    def construct_yaml_map(self, node):        data = OrderedDict()        yield data        value = self.construct_mapping(node)        data.update(value)    def construct_mapping(self, node, deep=False):        if isinstance(node, yaml.MappingNode): self.flatten_mapping(node)        else: raise yaml.constructor.ConstructorError(None, None,     'expected a mapping node, but found %s' % node.id, node.start_mark)        mapping = OrderedDict()        for key_node, value_node in node.value: key = self.construct_object(key_node, deep=deep) try:     hash(key) except TypeError, exc:     raise yaml.constructor.ConstructorError('while constructing a mapping',         node.start_mark, 'found unacceptable key (%s)' % exc, key_node.start_mark) value = self.construct_object(value_node, deep=deep) mapping[key] = value        return mapping


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