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?
这并没有解决最初的问题,但是对于像我这样在这里寻找提供此功能的库的人来说应该是有用的。
Addict是一个很棒的库:https://github.com/mewwts/addict它照顾了前面的答案中提到的许多问题。
文档中的一个例子:
body = {
'query': {
'filtered': {
'query': {
'match': {'description': 'addictive'}
},
'filter': {
'term': {'created_by': 'Mats'}
}
}
}
}
成瘾者:
from addict import Dict
body = Dict()
body.query.filtered.query.match.description = 'addictive'
body.query.filtered.filter.term.created_by = 'Mats'
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
很抱歉再添加一个,但这一个解决了subdicts和纠正AttributeError,尽管非常简单:
class DotDict(dict):
def __init__(self, d: dict = {}):
super().__init__()
for key, value in d.items():
self[key] = DotDict(value) if type(value) is dict else value
def __getattr__(self, key):
if key in self:
return self[key]
raise AttributeError(key) #Set proper exception, not KeyError
__setattr__ = dict.__setitem__
__delattr__ = dict.__delitem__