关于这个主题有很多问题，但我还没有能够调整解决方案来适应我的情况。假设我有一个从平面文件中获得的字典列表：
[{'Name': 'Jim', 'Attribute': 'Height', 'Value': '6.3'},
{'Name': 'Jim', 'Attribute': 'Weight', 'Value': '170'},
{'Name': 'Mary', 'Attribute': 'Height', 'Value': '5.5'},
{'Name': 'Mary', 'Attribute': 'Weight', 'Value': '140'}]
我想将其转换为嵌套字典，以便属性/值对与每个名称相关联：
{
'Jim': {'Height': '6.3', 'Weight': '170'},
'Mary': {'Height': '5.5', 'Weight': '140'}
}
使用 adefaultdict便于处理这些条目：
output = defaultdict(dict)
for person in people:
output[person['Name']][person['Attribute']] = person['Value']
这将产生提问者想要的数据结构，也便于他维护它：
"""
Module for managing nested dictionary collections.
"""
# nestdict.py by Adam Szieberth (2013)
# Python 3.3+
class NestedDict(dict):
"""
Class for managing nested dictionary structures. Normally, it works
like a builtin dictionary. However, if it gets a list as an argument,
it will iterate through that list assuming all elements of that list
as a key for the subdirectory chain.
NestedDict implements module level functions and makes managing nested
dictionary structure easier.
Instead of having a complicated way to manage extending or
overwriting, NestedDict has a lock property (not decorated!) which
allows or prohibits all alterations on the particular NestedDict
instance. Warning! If you do not pass a list (even if it has only one
element) to __setitem__, the superclass' method will be used which
sets the item regardless of lock state!
If you want more sophisticated behavior than full access/prohibition,
you can still use module level functions.
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.lock = False
def __getitem__(self, *args):
if isinstance(args[0], list):
return getitem(self, args[0])
return super().__getitem__(*args)
def __setitem__(self, *args):
if isinstance(args[0], list):
lock = self.get_lock(args[0])
if not lock:
return setitem(self, args[0], args[1],
overwrite=not lock, restruct=not lock,
dict_type=type(self))
else:
return False
else:
super().__setitem__(*args)
return True
def get_lock(self, path):
"""
Returns the state of lock on the given path. In fact it walks on
the path as long as possible, and returns the state of the last
lock it can get.
"""
lock = self.lock
level = 1
while level <= len(path):
try:
lock = getitem(self, path[:level]).lock
except (KeyError, AttributeError):
break
level += 1
return lock
def func_if_unlocked(self, *args):
"""
The default func_if_unlocked function for self.merge() method
which checks for lock on a path and returns True if path is
unlocked.
"""
path = args[0]
return not self.get_lock(path)
def lock_close(self, recursively=True):
"""
Locks locks.
"""
self.lock = True
if recursively:
for p in self.paths(of_values=False):
self.__getitem__(p).lock = True
def lock_open(self, recursively=True):
"""
Unlocks locks.
"""
self.lock = False
if recursively:
for p in self.paths(of_values=False):
self.__getitem__(p).lock = False
def merge(self, *dictobjs, restruct=True):
"""
Same as module level function merge. It needs less arguments
though since it uses self.func_if_unlocked() method to manage
extend and overwrite permissions.
"""
merge(self, *dictobjs,
func_if_extend=self.func_if_unlocked,
func_if_overwrite=self.func_if_unlocked,
restruct=restruct,
dict_type=type(self))
def paths(self, of_values=True):
"""
Same as module level function paths.
"""
return paths(self, of_values=of_values)
def getitem(dictobj, path):
"""
Returns the element of a nested dictionary structure which is on the
given path.
"""
_validate_path(path)
if len(path) == 1:
return dictobj[path[0]]
else:
return getitem(dictobj[path[0]], path[1:])
def setitem(dictobj, path, value, overwrite=True, restruct=True,
dict_type=dict):
"""
Sets a dictionary item on a given path to a given value.
- Returns True if value on path has been set.
- Returns False if there was a value on the given path which was not
overwritten by the function.
- Returns None if there was a value on the given path which was
identical to value.
If restruct=True then when a value blocks the path, that value get
cleared by an empty dictionary to make way forward.
"""
_validate_path(path)
try:
one_step = dictobj[path[0]]
except KeyError:
if len(path) == 1:
dictobj[path[0]] = value
return True
else:
dictobj[path[0]] = dict_type()
one_step = dictobj[path[0]]
else:
if len(path) == 1 and one_step == value:
return None
elif len(path) == 1 and overwrite is False:
return False
elif len(path) == 1 and overwrite is True:
dictobj[path[0]] = value
return True
else:
if not isinstance(one_step, dict):
if overwrite is True and restruct is True: ##TEST
dictobj[path[0]] = dict_type()
one_step = dictobj[path[0]]
else:
return False
return setitem(one_step, path[1:], value, overwrite=overwrite,
restruct=restruct, dict_type=dict_type)
def paths(dictobj, of_values=True, past_keys=[]):
"""
Generator to iterate through branches. Used by merge function, but
can be useful for other object management stuffs.
By default it returns paths of values. However, if of_values=False
then it returns the paths of all subdirectories.
"""
for key in dictobj.keys():
path = past_keys + [key]
if not isinstance(dictobj[key], dict):
if of_values is True:
yield path
else:
if of_values is False:
yield path
yield from paths(dictobj[key], of_values=of_values,
past_keys=path)
def merge(*dictobjs,
func_if_extend=True,
func_if_overwrite=True,
restruct=True,
dict_type=dict,
return_new=False):
"""
Merges one dictionary with one or more another.
By default it mutates the first dictobj. However, if return_new=True
then it returns a new dictionary object typed recursively to
dict_type. If you want no retypeing, use copy.deepcopy(), and pass the
copied dictionary as first argument.
To make mergeing more flexible, you are able to control how extension
overwriting should be done (both are allowed by default). By setting
func_if_overwrite to False, overwriting becomes disabled. By setting
func_if_extend to False, extension becomes disabled and you can only
update existing values if overwriting is enabled. If both are
disabled, no alteration will be made, so this scenario makes no sense,
but allowed.
Moreover you can pass functions to the two mentioned arguments which
will be called with the path (list of keys), dictobj1, dictobj2
arguments and expected to return True or False.
"""
if return_new is True:
d = retype(dictobjs[0], dict_type)
elif return_new is False:
d = dictobjs[0]
for dictobj in dictobjs[1:]:
for p in paths(dictobj):
try:
getitem(d, p)
except KeyError:
if hasattr(func_if_extend, '__call__'):
ex = func_if_extend(p, d, dictobj)
else:
ex = func_if_extend
if ex:
setitem(d, p, getitem(dictobj, p),
dict_type=dict_type)
else:
if getitem(d, p) != getitem(dictobj, p):
if hasattr(func_if_overwrite, '__call__'):
ow = func_if_overwrite(p, d, dictobj)
else:
ow = func_if_overwrite
restruct_ = restruct and ow
setitem(d, p, getitem(dictobj, p),
overwrite=ow,
restruct=restruct_,
dict_type=dict_type)
return d
def retype(dictobj, dict_type):
"""
Recursively modifies the type of a dictionary object and returns a new
dictionary of type dict_type. You can also use this function instead
of copy.deepcopy() for dictionaries.
"""
def walker(dictobj):
for k in dictobj.keys():
if isinstance(dictobj[k], dict):
yield (k, dict_type(walker(dictobj[k])))
else:
yield (k, dictobj[k])
d = dict_type(walker(dictobj))
return d
def _validate_path(path):
if not isinstance(path, list):
raise TypeError('path argument have to be a list')
if not path:
raise Exception('path argument have to be a nonempty list')
def main():
import pprint
print('nestdict.py by Adam Szieberth')
print(__doc__)
print('Example for Stack Overflow question #635483:\n')
inp_data =[(['new jersey', 'mercer county', 'plumbers'], 3),
(['new jersey', 'mercer county', 'programmers'], 81),
(['new jersey', 'middlesex county', 'programmers'], 81),
(['new jersey', 'middlesex county', 'salesmen'], 62),
(['new york', 'queens county', 'plumbers'], 9),
(['new york', 'queens county', 'salesmen'], 36)]
print('Input data:\n')
pprint.PrettyPrinter(indent=1).pprint(inp_data)
print('\n>>> data = NestedDict()')
data = NestedDict()
print('>>> for d in inp_data:')
print('>>> data[d[0]] = d[1]\n')
for d in inp_data:
data[d[0]] = d[1]
print('Result:\n')
pprint.PrettyPrinter(indent=0).pprint(data)
return data
if __name__ == '__main__':
data = main()
路径（）的一个例子：https ://stackoverflow.com/a/16298347/2334951
我打算在未来为其添加更多功能。您可以在这里找到最新版本：https ://github.com/gneposis/gntools/blob/master/src/gntools/core/collections/nestdict.py
还涵盖了这些问题：
编辑：更新到新的和经过测试的版本。
用法：
>>> d = [{'name': 'Jim', 'attribute': 'Height', 'value': 6.3},
... {'name': 'Jim', 'attribute': 'Weight', 'value': 170},
... {'name': 'Mary', 'attribute': 'Height', 'value': 5.5},
... {'name': 'Mary', 'attribute': 'Weight', 'value': 140}, ]
>>> result = NestedDict()
>>> for i in d:
... path = [i['name'], i['attribute']] # list of keys in order of nesting
... result[path] = i['value']
>>> print(result)
{'Mary': {'Height': 5.5, 'Weight': 140}, 'Jim': {'Height': 6.3, 'Weight': 170}}