我发现它更方便访问字典键作为obj。foo而不是obj['foo'],所以我写了这个片段:

class AttributeDict(dict):
    def __getattr__(self, attr):
        return self[attr]
    def __setattr__(self, attr, value):
        self[attr] = value

然而,我认为一定有一些原因,Python没有提供开箱即用的功能。以这种方式访问字典键的注意事项和缺陷是什么?


当前回答

您可以使用dict_to_obj https://pypi.org/project/dict-to-obj/ 它完全符合你的要求

From dict_to_obj import DictToObj
a = {
'foo': True
}
b = DictToObj(a)
b.foo
True

其他回答

让我发布另一个实现,它基于Kinvais的答案,但集成了http://databio.org/posts/python_AttributeDict.html中提出的AttributeDict的思想。

这个版本的优点是它也适用于嵌套字典:

class AttrDict(dict):
    """
    A class to convert a nested Dictionary into an object with key-values
    that are accessible using attribute notation (AttrDict.attribute) instead of
    key notation (Dict["key"]). This class recursively sets Dicts to objects,
    allowing you to recurse down nested dicts (like: AttrDict.attr.attr)
    """

    # Inspired by:
    # http://stackoverflow.com/a/14620633/1551810
    # http://databio.org/posts/python_AttributeDict.html

    def __init__(self, iterable, **kwargs):
        super(AttrDict, self).__init__(iterable, **kwargs)
        for key, value in iterable.items():
            if isinstance(value, dict):
                self.__dict__[key] = AttrDict(value)
            else:
                self.__dict__[key] = value

元组可以使用字典键。如何在构造中访问元组?

另外,namedtuple是一种方便的结构,可以通过属性访问提供值。

class AttrDict(dict):

     def __init__(self):
           self.__dict__ = self

if __name__ == '____main__':

     d = AttrDict()
     d['ray'] = 'hope'
     d.sun = 'shine'  >>> Now we can use this . notation
     print d['ray']
     print d.sun

从另一个SO问题中,有一个很好的实现示例,可以简化现有的代码。如何:

class AttributeDict(dict):
    __slots__ = () 
    __getattr__ = dict.__getitem__
    __setattr__ = dict.__setitem__

更加简洁,并且不会为将来的__getattr__和__setattr__函数留下任何额外的麻烦空间。

解决方案是:

DICT_RESERVED_KEYS = vars(dict).keys()


class SmartDict(dict):
    """
    A Dict which is accessible via attribute dot notation
    """
    def __init__(self, *args, **kwargs):
        """
        :param args: multiple dicts ({}, {}, ..)
        :param kwargs: arbitrary keys='value'

        If ``keyerror=False`` is passed then not found attributes will
        always return None.
        """
        super(SmartDict, self).__init__()
        self['__keyerror'] = kwargs.pop('keyerror', True)
        [self.update(arg) for arg in args if isinstance(arg, dict)]
        self.update(kwargs)

    def __getattr__(self, attr):
        if attr not in DICT_RESERVED_KEYS:
            if self['__keyerror']:
                return self[attr]
            else:
                return self.get(attr)
        return getattr(self, attr)

    def __setattr__(self, key, value):
        if key in DICT_RESERVED_KEYS:
            raise AttributeError("You cannot set a reserved name as attribute")
        self.__setitem__(key, value)

    def __copy__(self):
        return self.__class__(self)

    def copy(self):
        return self.__copy__()