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
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。
其他回答
由于以下原因，我对现有的选项不满意，于是我开发了MetaDict。它的行为完全类似于dict，但支持点表示法和IDE自动补全，而没有其他解决方案的缺点和潜在的名称空间冲突。所有功能和使用示例都可以在GitHub上找到(见上面的链接)。
完全披露:我是MetaDict的作者。
我在尝试其他解决方案时遇到的缺点/限制:
Addict No key autocompletion in IDE Nested key assignment cannot be turned off Newly assigned dict objects are not converted to support attribute-style key access Shadows inbuilt type Dict Prodict No key autocompletion in IDE without defining a static schema (similar to dataclass) No recursive conversion of dict objects when embedded in list or other inbuilt iterables AttrDict No key autocompletion in IDE Converts list objects to tuple behind the scenes Munch Inbuilt methods like items(), update(), etc. can be overwritten with obj.items = [1, 2, 3] No recursive conversion of dict objects when embedded in list or other inbuilt iterables EasyDict Only strings are valid keys, but dict accepts all hashable objects as keys Inbuilt methods like items(), update(), etc. can be overwritten with obj.items = [1, 2, 3] Inbuilt methods don't behave as expected: obj.pop('unknown_key', None) raises an AttributeError
如果使用数组表示法，则可以将所有合法字符串字符作为键的一部分。 例如，obj['!#$%^&*()_']
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。
这个答案摘自Luciano Ramalho的《流利的Python》一书。这要归功于那个家伙。
class AttrDict:
"""A read-only façade for navigating a JSON-like object
using attribute notation
"""
def __init__(self, mapping):
self._data = dict(mapping)
def __getattr__(self, name):
if hasattr(self._data, name):
return getattr(self._data, name)
else:
return AttrDict.build(self._data[name])
@classmethod
def build(cls, obj):
if isinstance(obj, Mapping):
return cls(obj)
elif isinstance(obj, MutableSequence):
return [cls.build(item) for item in obj]
else:
return obj
in the init we are taking the dict and making it a dictionary. when getattr is used we try to get the attribute from the dict if the dict already has that attribute. or else we are passing the argument to a class method called build. now build does the intresting thing. if the object is dict or a mapping like that, the that object is made an attr dict itself. if it's a sequence like list, it's passed to the build function we r on right now. if it's anythin else, like str or int. return the object itself.
显然，现在有一个库- https://pypi.python.org/pypi/attrdict -实现了这个确切的功能，加上递归合并和json加载。也许值得一看。
