一个简单的类，可以包装字典，并根据键进行检索:

class FindKey(dict):
    def get(self, path, default=None):
        keys = path.split(".")
        val = None

        for key in keys:
            if val:
                if isinstance(val, list):
                    val = [v.get(key, default) if v else None for v in val]
                else:
                    val = val.get(key, default)
            else:
                val = dict.get(self, key, default)

            if not val:
                break

        return val

例如:

person = {'person':{'name':{'first':'John'}}}
FindDict(person).get('person.name.first') # == 'John'

如果该键不存在，则默认返回None。你可以在FindDict包装器中使用default=键覆盖它，例如':

FindDict(person, default='').get('person.name.last') # == doesn't exist, so ''

一个简单的类，可以包装字典，并根据键进行检索:

class FindKey(dict):
    def get(self, path, default=None):
        keys = path.split(".")
        val = None

        for key in keys:
            if val:
                if isinstance(val, list):
                    val = [v.get(key, default) if v else None for v in val]
                else:
                    val = val.get(key, default)
            else:
                val = dict.get(self, key, default)

            if not val:
                break

        return val

例如:

person = {'person':{'name':{'first':'John'}}}
FindDict(person).get('person.name.first') # == 'John'

如果该键不存在，则默认返回None。你可以在FindDict包装器中使用default=键覆盖它，例如':

FindDict(person, default='').get('person.name.last') # == doesn't exist, so ''

我的实现下降到子字典，忽略None值，但失败与TypeError如果发现任何其他

def deep_get(d: dict, *keys, default=None):
    """ Safely get a nested value from a dict

    Example:
        config = {'device': None}
        deep_get(config, 'device', 'settings', 'light')
        # -> None
        
    Example:
        config = {'device': True}
        deep_get(config, 'device', 'settings', 'light')
        # -> TypeError

    Example:
        config = {'device': {'settings': {'light': 'bright'}}}
        deep_get(config, 'device', 'settings', 'light')
        # -> 'light'

    Note that it returns `default` is a key is missing or when it's None.
    It will raise a TypeError if a value is anything else but a dict or None.
    
    Args:
        d: The dict to descend into
        keys: A sequence of keys to follow
        default: Custom default value
    """
    # Descend while we can
    try:
        for k in keys:
            d = d[k]
    # If at any step a key is missing, return default
    except KeyError:
        return default
    # If at any step the value is not a dict...
    except TypeError:
        # ... if it's a None, return default. Assume it would be a dict.
        if d is None:
            return default
        # ... if it's something else, raise
        else:
            raise
    # If the value was found, return it
    else:
        return d

你可以用虚线:

PIP安装

from dotted.collection import DottedDict

assert DottedDict(dict(foo=dict(bar="baz")))["foo"]["bar"] == "baz"
assert DottedDict(dict(foo=dict(bar="baz")))["foo.bar"] == "baz"
assert DottedDict(dict(foo=dict(bar="baz"))).get("lorem.ipsum", None) is None
assert DottedDict(dict(foo=dict(bar="baz"))).get("lorem.ipsum", "default") == "default"

因为如果缺少一个键就会引发一个键错误是合理的，我们甚至可以不检查它，让它像这样单一:

def get_dict(d, kl):
  cur = d[kl[0]]
  return get_dict(cur, kl[1:]) if len(kl) > 1 else cur

我改编了GenesRus和unutbu的答案，非常简单:

class new_dict(dict):
    def deep_get(self, *args, default=None):
        _empty_dict = {}
        out = self
        for key in args:
            out = out.get(key, _empty_dict)
        return out if out else default

它适用于:

d = new_dict(some_data)
d.deep_get("key1", "key2", "key3", ..., default=some_value)