我如何使Python字典成员访问通过点“。”?

例如,我想写mydict.val而不是mydict['val']。

我还想以这种方式访问嵌套字典。例如

mydict.mydict2.val 

会提到

mydict = { 'mydict2': { 'val': ... } }

当前回答

使用__getattr__,非常简单,适用于 Python 3.4.3

class myDict(dict):
    def __getattr__(self,val):
        return self[val]


blockBody=myDict()
blockBody['item1']=10000
blockBody['item2']="StackOverflow"
print(blockBody.item1)
print(blockBody.item2)

输出:

10000
StackOverflow

其他回答

一个很微妙的解

class DotDict(dict):

    __setattr__ = dict.__setitem__
    __delattr__ = dict.__delitem__

    def __getattr__(self, key):

        def typer(candidate):
            if isinstance(candidate, dict):
                return DotDict(candidate)

            if isinstance(candidate, str):  # iterable but no need to iter
                return candidate

            try:  # other iterable are processed as list
                return [typer(item) for item in candidate]
            except TypeError:
                return candidate

            return candidate

        return typer(dict.get(self, key))

不是对OP问题的直接回答,但受到启发,也许对一些人有用。我已经创建了一个基于对象的解决方案使用内部__dict__(在任何方式优化代码)

payload = {
    "name": "John",
    "location": {
        "lat": 53.12312312,
        "long": 43.21345112
    },
    "numbers": [
        {
            "role": "home",
            "number": "070-12345678"
        },
        {
            "role": "office",
            "number": "070-12345679"
        }
    ]
}


class Map(object):
    """
    Dot style access to object members, access raw values
    with an underscore e.g.

    class Foo(Map):
        def foo(self):
            return self.get('foo') + 'bar'

    obj = Foo(**{'foo': 'foo'})

    obj.foo => 'foobar'
    obj._foo => 'foo'

    """

    def __init__(self, *args, **kwargs):
        for arg in args:
            if isinstance(arg, dict):
                for k, v in arg.iteritems():
                    self.__dict__[k] = v
                    self.__dict__['_' + k] = v

        if kwargs:
            for k, v in kwargs.iteritems():
                self.__dict__[k] = v
                self.__dict__['_' + k] = v

    def __getattribute__(self, attr):
        if hasattr(self, 'get_' + attr):
            return object.__getattribute__(self, 'get_' + attr)()
        else:
            return object.__getattribute__(self, attr)

    def get(self, key):
        try:
            return self.__dict__.get('get_' + key)()
        except (AttributeError, TypeError):
            return self.__dict__.get(key)

    def __repr__(self):
        return u"<{name} object>".format(
            name=self.__class__.__name__
        )


class Number(Map):
    def get_role(self):
        return self.get('role')

    def get_number(self):
        return self.get('number')


class Location(Map):
    def get_latitude(self):
        return self.get('lat') + 1

    def get_longitude(self):
        return self.get('long') + 1


class Item(Map):
    def get_name(self):
        return self.get('name') + " Doe"

    def get_location(self):
        return Location(**self.get('location'))

    def get_numbers(self):
        return [Number(**n) for n in self.get('numbers')]


# Tests

obj = Item({'foo': 'bar'}, **payload)

assert type(obj) == Item
assert obj._name == "John"
assert obj.name == "John Doe"
assert type(obj.location) == Location
assert obj.location._lat == 53.12312312
assert obj.location._long == 43.21345112
assert obj.location.latitude == 54.12312312
assert obj.location.longitude == 44.21345112

for n in obj.numbers:
    assert type(n) == Number
    if n.role == 'home':
        assert n.number == "070-12345678"
    if n.role == 'office':
        assert n.number == "070-12345679"

@derek73的答案非常简洁,但它不能被pickle或(深度)复制,并且它在缺少键时返回None。下面的代码修复了这个问题。

编辑:我没有看到上面的答案解决了完全相同的问题(点赞)。我把答案留在这里供参考。

class dotdict(dict):
    __setattr__ = dict.__setitem__
    __delattr__ = dict.__delitem__

    def __getattr__(self, name):
        try:
            return self[name]
        except KeyError:
            raise AttributeError(name)

我喜欢Munch,它提供了很多方便的选项在点访问。

进口蒙克 Temp_1 = {'person': {' fname': 'senthil', 'lname': 'ramalingam'}} Dict_munch = munch.munchify(temp_1) dict_munch.person.fname

不喜欢。在Python中,属性访问和索引是分开的事情,您不应该希望它们执行相同的操作。创建一个类(可能是由namedtuple创建的),如果你有一些应该具有可访问属性的东西,并使用[]符号从字典中获取一个项。