将旧字典列表与新字典列表进行比较，以发现所有列表对象的键和值之间的差异

Question

[StackOverflow上有大量关于直接old dict与new dict进行比较的问答，

• 我想将旧的字典列表与新的字典列表进行比较，并找到要删除，添加，更新的内容。

old_dict = [{'name':'john','age':10},{'name':'cena','age':26},{'name':'tom','age':24}]
new_dict = [{'name':'cena','age':26},{'name':'john','age':13},{'name':'henry','age':32},{'name':'steave','age':50}]

我想将old_dict和new_dict作为参数传递给该函数，在该函数中比较键，所有列表对象中的值以及该函数将返回以下字段

return updated_key_val,added_key_val,removed_new_key_val

print(updated_key_val)
>> [{'name':'john','age':13}] ### age value updated from 10 to 13

print(added_key_val)
>> [{'name':'henry','age':32},{'name':'steave','age':50}] ## old results doesn't had this 2 dicts so this are new dicts

print(removed_new_key_val)
>> [{'name':'tom','age':24}] ## this has been removed in newer results

Answer 1

由于'name'字段相等时每个字典都被认为是相等的，因此您可以对这些旧名称建立索引，然后在对新条目进行一次迭代后跟踪更新，添加和删除的]]

def entries_diff(old_entries, new_entries):
    updated, added = [], []
    old_index = {e['name']: e for e in old_entries}
    for e in new_entries:
        name = e['name']
        if name not in old_index:
            added.append(e)
        else:
            old = old_index[name]
            if old != e:
                updated.append(e)
            del old_index[name]

    removed = list(old_index.values())
    return updated, added, removed