Il s'agit d'une ancienne question et elle demande un peu moins que ce dont j'avais besoin, donc cette réponse résout en fait plus que cette question ne demande. Les réponses à cette question m'ont aidé à résoudre les problèmes suivants :
- (demandé) Enregistrez les différences entre deux dictionnaires
- Fusionner les différences du #1 dans le dictionnaire de base
- (demandé) Fusionner les différences entre deux dictionnaires (traiter le dictionnaire #2 comme s'il était un dictionnaire diff)
- Essayez de détecter les mouvements des articles ainsi que les changements
- (demandé) Faire tout cela récursivement
Tout cela, combiné à JSON, constitue un support de stockage de configuration assez puissant.
La solution ( également sur github ):
from collections import OrderedDict
from pprint import pprint
class izipDestinationMatching(object):
__slots__ = ("attr", "value", "index")
def __init__(self, attr, value, index):
self.attr, self.value, self.index = attr, value, index
def __repr__(self):
return "izip_destination_matching: found match by '%s' = '%s' @ %d" % (self.attr, self.value, self.index)
def izip_destination(a, b, attrs, addMarker=True):
"""
Returns zipped lists, but final size is equal to b with (if shorter) a padded with nulls
Additionally also tries to find item reallocations by searching child dicts (if they are dicts) for attribute, listed in attrs)
When addMarker == False (patching), final size will be the longer of a, b
"""
for idx, item in enumerate(b):
try:
attr = next((x for x in attrs if x in item), None) # See if the item has any of the ID attributes
match, matchIdx = next(((orgItm, idx) for idx, orgItm in enumerate(a) if attr in orgItm and orgItm[attr] == item[attr]), (None, None)) if attr else (None, None)
if match and matchIdx != idx and addMarker: item[izipDestinationMatching] = izipDestinationMatching(attr, item[attr], matchIdx)
except:
match = None
yield (match if match else a[idx] if len(a) > idx else None), item
if not addMarker and len(a) > len(b):
for item in a[len(b) - len(a):]:
yield item, item
def dictdiff(a, b, searchAttrs=[]):
"""
returns a dictionary which represents difference from a to b
the return dict is as short as possible:
equal items are removed
added / changed items are listed
removed items are listed with value=None
Also processes list values where the resulting list size will match that of b.
It can also search said list items (that are dicts) for identity values to detect changed positions.
In case such identity value is found, it is kept so that it can be re-found during the merge phase
@param a: original dict
@param b: new dict
@param searchAttrs: list of strings (keys to search for in sub-dicts)
@return: dict / list / whatever input is
"""
if not (isinstance(a, dict) and isinstance(b, dict)):
if isinstance(a, list) and isinstance(b, list):
return [dictdiff(v1, v2, searchAttrs) for v1, v2 in izip_destination(a, b, searchAttrs)]
return b
res = OrderedDict()
if izipDestinationMatching in b:
keepKey = b[izipDestinationMatching].attr
del b[izipDestinationMatching]
else:
keepKey = izipDestinationMatching
for key in sorted(set(a.keys() + b.keys())):
v1 = a.get(key, None)
v2 = b.get(key, None)
if keepKey == key or v1 != v2: res[key] = dictdiff(v1, v2, searchAttrs)
if len(res) <= 1: res = dict(res) # This is only here for pretty print (OrderedDict doesn't pprint nicely)
return res
def dictmerge(a, b, searchAttrs=[]):
"""
Returns a dictionary which merges differences recorded in b to base dictionary a
Also processes list values where the resulting list size will match that of a
It can also search said list items (that are dicts) for identity values to detect changed positions
@param a: original dict
@param b: diff dict to patch into a
@param searchAttrs: list of strings (keys to search for in sub-dicts)
@return: dict / list / whatever input is
"""
if not (isinstance(a, dict) and isinstance(b, dict)):
if isinstance(a, list) and isinstance(b, list):
return [dictmerge(v1, v2, searchAttrs) for v1, v2 in izip_destination(a, b, searchAttrs, False)]
return b
res = OrderedDict()
for key in sorted(set(a.keys() + b.keys())):
v1 = a.get(key, None)
v2 = b.get(key, None)
#print "processing", key, v1, v2, key not in b, dictmerge(v1, v2)
if v2 is not None: res[key] = dictmerge(v1, v2, searchAttrs)
elif key not in b: res[key] = v1
if len(res) <= 1: res = dict(res) # This is only here for pretty print (OrderedDict doesn't pprint nicely)
return res
