python - 嵌套字典的类对象属性访问

Question

我正在使用一个返回嵌套字典的包。当其他一切都在对象语法中时，使用字典语法在我的类方法中访问这个返回对象感觉很尴尬。搜索将我带到了 bunch/neobunch 包，这似乎实现了我所追求的。我还看到建议使用 namedtuples，但它们不容易支持嵌套属性，而且大多数解决方案都依赖于在 namedtuple 中使用字典进行嵌套。

什么是更自然的实现方式？

data = {'a': 'aval', 'b': {'b1':{'b2a':{'b3a':'b3aval','b3b':'b3bval'},'b2b':'b2bval'}} }

print(data['b']['b1']['b2a']['b3b'])  # dictionary access
# print(data.b.b1.b2a.b3b)  # desired access

import neobunch
data1 = neobunch.bunchify(data)
print(data1.b.b1.b2a.b3b)

Answer 1

下面的类可以让你做你想做的事(适用于 Python 2 和 3):

class AttrDict(dict):
    """ Dictionary subclass whose entries can be accessed by attributes (as well
        as normally).

    >>> obj = AttrDict()
    >>> obj['test'] = 'hi'
    >>> print obj.test
    hi
    >>> del obj.test
    >>> obj.test = 'bye'
    >>> print obj['test']
    bye
    >>> print len(obj)
    1
    >>> obj.clear()
    >>> print len(obj)
    0
    """
    def __init__(self, *args, **kwargs):
        super(AttrDict, self).__init__(*args, **kwargs)
        self.__dict__ = self

    @classmethod
    def from_nested_dicts(cls, data):
        """ Construct nested AttrDicts from nested dictionaries. """
        if not isinstance(data, dict):
            return data
        else:
            return cls({key: cls.from_nested_dicts(data[key]) for key in data})


if __name__ == '__main__':

    data = {
        "a": "aval",
        "b": {
            "b1": {
                "b2b": "b2bval",
                "b2a": {
                    "b3a": "b3aval",
                    "b3b": "b3bval"
                }
            }
        }
    }

    attrdict = AttrDict.from_nested_dicts(data)
    print(attrdict.b.b1.b2a.b3b)  # -> b3bval