我正在寻找一种优雅的方式来获得数据使用属性访问字典与一些嵌套的字典和列表(即javascript风格的对象语法)。
例如:
>>> d = {'a': 1, 'b': {'c': 2}, 'd': ["hi", {'foo': "bar"}]}
应该以这样的方式访问:
>>> x = dict2obj(d)
>>> x.a
1
>>> x.b.c
2
>>> x.d[1].foo
bar
我想,如果没有递归,这是不可能的,但是有什么更好的方法来获得字典的对象样式呢?
我正在寻找一种优雅的方式来获得数据使用属性访问字典与一些嵌套的字典和列表(即javascript风格的对象语法)。
例如:
>>> d = {'a': 1, 'b': {'c': 2}, 'd': ["hi", {'foo': "bar"}]}
应该以这样的方式访问:
>>> x = dict2obj(d)
>>> x.a
1
>>> x.b.c
2
>>> x.d[1].foo
bar
我想,如果没有递归,这是不可能的,但是有什么更好的方法来获得字典的对象样式呢?
当前回答
class Dict2Obj:
def __init__(self, json_data):
self.convert(json_data)
def convert(self, json_data):
if not isinstance(json_data, dict):
return
for key in json_data:
if not isinstance(json_data[key], dict):
self.__dict__.update({key: json_data[key]})
else:
self.__dict__.update({ key: Dict2Obj(json_data[key])})
我找不到嵌套字典到对象的实现,所以写了一个。
用法:
>>> json_data = {"a": {"b": 2}, "c": 3}
>>> out_obj = Dict2Obj(json_data)
>>> out_obj.a
<Dict2Obj object at 0x7f3dc22c2d68>
>>> out_obj.a.b
2
>>> out_obj.a.c
3
其他回答
在@max-sirwa的代码上更新了递归数组展开
class Objectify:
def __init__(self, **kwargs):
for key, value in kwargs.items():
if isinstance(value, dict):
f = Objectify(**value)
self.__dict__.update({key: f})
elif isinstance(value, list):
t = []
for i in value:
t.append(Objectify(**i)) if isinstance(i, dict) else t.append(i)
self.__dict__.update({key: t})
else:
self.__dict__.update({key: value})
这是另一个实现:
class DictObj(object):
def __init__(self, d):
self.__dict__ = d
def dict_to_obj(d):
if isinstance(d, (list, tuple)): return map(dict_to_obj, d)
elif not isinstance(d, dict): return d
return DictObj(dict((k, dict_to_obj(v)) for (k,v) in d.iteritems()))
[编辑]遗漏了在列表中处理字典的部分,而不仅仅是其他字典。添加修复。
在2021年,使用pydantic BaseModel -将嵌套字典和嵌套json对象转换为python对象,反之亦然:
https://pydantic-docs.helpmanual.io/usage/models/
>>> class Foo(BaseModel):
... count: int
... size: float = None
...
>>>
>>> class Bar(BaseModel):
... apple = 'x'
... banana = 'y'
...
>>>
>>> class Spam(BaseModel):
... foo: Foo
... bars: List[Bar]
...
>>>
>>> m = Spam(foo={'count': 4}, bars=[{'apple': 'x1'}, {'apple': 'x2'}])
对象to dict
>>> print(m.dict())
{'foo': {'count': 4, 'size': None}, 'bars': [{'apple': 'x1', 'banana': 'y'}, {'apple': 'x2', 'banana': 'y'}]}
对象转换为JSON
>>> print(m.json())
{"foo": {"count": 4, "size": null}, "bars": [{"apple": "x1", "banana": "y"}, {"apple": "x2", "banana": "y"}]}
反对的词典
>>> spam = Spam.parse_obj({'foo': {'count': 4, 'size': None}, 'bars': [{'apple': 'x1', 'banana': 'y'}, {'apple': 'x2', 'banana': 'y2'}]})
>>> spam
Spam(foo=Foo(count=4, size=None), bars=[Bar(apple='x1', banana='y'), Bar(apple='x2', banana='y2')])
JSON到对象
>>> spam = Spam.parse_raw('{"foo": {"count": 4, "size": null}, "bars": [{"apple": "x1", "banana": "y"}, {"apple": "x2", "banana": "y"}]}')
>>> spam
Spam(foo=Foo(count=4, size=None), bars=[Bar(apple='x1', banana='y'), Bar(apple='x2', banana='y')])
我认为字典由数字、字符串和字典组成,大多数时候就足够了。 所以我忽略了元组、列表和其他类型没有出现在字典的最后一个维度的情况。
考虑了继承,结合递归,方便地解决了打印问题,并提供了两种数据查询方式,一种数据编辑方式。
请看下面的例子,这是一个描述学生信息的词典:
group=["class1","class2","class3","class4",]
rank=["rank1","rank2","rank3","rank4","rank5",]
data=["name","sex","height","weight","score"]
#build a dict based on the lists above
student_dic=dict([(g,dict([(r,dict([(d,'') for d in data])) for r in rank ]))for g in group])
#this is the solution
class dic2class(dict):
def __init__(self, dic):
for key,val in dic.items():
self.__dict__[key]=self[key]=dic2class(val) if isinstance(val,dict) else val
student_class=dic2class(student_dic)
#one way to edit:
student_class.class1.rank1['sex']='male'
student_class.class1.rank1['name']='Nan Xiang'
#two ways to query:
print student_class.class1.rank1
print student_class.class1['rank1']
print '-'*50
for rank in student_class.class1:
print getattr(student_class.class1,rank)
结果:
{'score': '', 'sex': 'male', 'name': 'Nan Xiang', 'weight': '', 'height': ''}
{'score': '', 'sex': 'male', 'name': 'Nan Xiang', 'weight': '', 'height': ''}
--------------------------------------------------
{'score': '', 'sex': '', 'name': '', 'weight': '', 'height': ''}
{'score': '', 'sex': '', 'name': '', 'weight': '', 'height': ''}
{'score': '', 'sex': 'male', 'name': 'Nan Xiang', 'weight': '', 'height': ''}
{'score': '', 'sex': '', 'name': '', 'weight': '', 'height': ''}
{'score': '', 'sex': '', 'name': '', 'weight': '', 'height': ''}
下面是一个使用namedtuple的嵌套就绪版本:
from collections import namedtuple
class Struct(object):
def __new__(cls, data):
if isinstance(data, dict):
return namedtuple(
'Struct', data.iterkeys()
)(
*(Struct(val) for val in data.values())
)
elif isinstance(data, (tuple, list, set, frozenset)):
return type(data)(Struct(_) for _ in data)
else:
return data
=>
>>> d = {'a': 1, 'b': {'c': 2}, 'd': ["hi", {'foo': "bar"}]}
>>> s = Struct(d)
>>> s.d
['hi', Struct(foo='bar')]
>>> s.d[0]
'hi'
>>> s.d[1].foo
'bar'