如何用DeepDiff比较字典列表并原地修改（或生成新字典列表）

问题场景 #

有两个包含字典的列表dict_1和dict_2，通过deepdiff库的DeepDiff工具对比后得到值变更结果，需要将dict_1中对应的值用dict_2的修改值原地覆盖，或者生成新的字典列表dict_3。

原测试代码及执行结果：

import deepdiff

dict_1 = [{"id": "first", "name": "first"}, {"id": "second", "name": "second"}, {"id": "third", "name": "third"}]
dict_2 = [{"id": "first", "name": "first"}, {"id": "second modified", "name": "second modified"}, {"id": "third", "name": "third"}]

diff = deepdiff.DeepDiff(dict_1, dict_2).get('values_changed',{})
print(diff)

执行输出：

{"root[1]['id']": {'new_value': 'second modified', 'old_value': 'second'}, "root[1]['name']": {'new_value': 'second modified', 'old_value': 'second'}}

期望得到的更新后结果：

dict_1 = [{"id": "first", "name": "first"}, {"id": "second modified", "name": "second modified"}, {"id": "third", "name": "third"}]

解决方案 #

1. 原地覆盖更新dict_1 #

通过解析DeepDiff返回的路径字符串，定位到dict_1中的目标元素，直接修改对应值：

import deepdiff

dict_1 = [{"id": "first", "name": "first"}, {"id": "second", "name": "second"}, {"id": "third", "name": "third"}]
dict_2 = [{"id": "first", "name": "first"}, {"id": "second modified", "name": "second modified"}, {"id": "third", "name": "third"}]

diff = deepdiff.DeepDiff(dict_1, dict_2).get('values_changed', {})

# 遍历变更项，原地更新dict_1
for path, change_info in diff.items():
    # 解析路径：提取列表索引和字典键
    path_content = path.replace("root", "").strip()
    # 获取列表索引（如root[1]中的1）
    list_index = int(path_content.split('[')[1].split(']')[0])
    # 获取字典键（如['id']中的id）
    dict_key = path_content.split("['")[1].split("']")[0]
    # 覆盖原数值
    dict_1[list_index][dict_key] = change_info['new_value']

print(dict_1)

2. 生成新字典列表dict_3（不修改原数据） #

如果不想改动原dict_1，可以先深拷贝原列表，再在拷贝后的新列表上修改：

import copy
import deepdiff

dict_1 = [{"id": "first", "name": "first"}, {"id": "second", "name": "second"}, {"id": "third", "name": "third"}]
dict_2 = [{"id": "first", "name": "first"}, {"id": "second modified", "name": "second modified"}, {"id": "third", "name": "third"}]

diff = deepdiff.DeepDiff(dict_1, dict_2).get('values_changed', {})

# 深拷贝生成新列表，避免修改原数据
dict_3 = copy.deepcopy(dict_1)

for path, change_info in diff.items():
    path_content = path.replace("root", "").strip()
    list_index = int(path_content.split('[')[1].split(']')[0])
    dict_key = path_content.split("['")[1].split("']")[0]
    dict_3[list_index][dict_key] = change_info['new_value']

print("原dict_1:", dict_1)
print("更新后的dict_3:", dict_3)

内容的提问来源于stack exchange，提问作者saromba