如何对比两个嵌套字典？实现差异输出方案问询

我有两个嵌套结构的字典：

old_state = {
    'https://github.com/search?q=i+love+python': {'title': 'i love python', 'repo_count': '517'},
    'https://github.com/search?q=python+3': {'title': 'python 3', 'repo_count': '101K'},
    'https://github.com/search?q=world': {'title': 'world', 'repo_count': '1M'},
    'https://github.com/search?q=hello+world': {'title': 'hello world', 'repo_count': '1M'}
}

new_state = {
    'https://github.com/search?q=python+3': {'title': 'python 3', 'repo_count': '102K'},
    'https://github.com/search?q=world': {'title': 'world', 'repo_count': '1M'},
    'https://github.com/search?q=hello+world': {'title': 'hello world', 'repo_count': '1M'},
    'https://github.com/search?q=i+love+python': {'title': 'i love python', 'repo_count': '517'}
}

目前我已经能实现单层字典的差异对比输出：

old_state = {'title': 'i love python', 'repo_count': '517'}
new_state = {'title': 'python 3', 'repo_count': '102K'}

if old_state['title'] != new_state['title']:
   print('new change in title')
if old_state['repo_count'] != new_state['repo_count']:
   print('new change in repo count')

现在希望对上述嵌套字典实现类似的差异检测并输出对应提示，请问是否可行？若可行，该如何实现？

完全可行，你可以通过遍历嵌套字典的外层键，再对比内层字段的方式实现，同时还能处理键新增/删除的情况。以下是具体实现代码：

old_state = {
    'https://github.com/search?q=i+love+python': {'title': 'i love python', 'repo_count': '517'},
    'https://github.com/search?q=python+3': {'title': 'python 3', 'repo_count': '101K'},
    'https://github.com/search?q=world': {'title': 'world', 'repo_count': '1M'},
    'https://github.com/search?q=hello+world': {'title': 'hello world', 'repo_count': '1M'}
}

new_state = {
    'https://github.com/search?q=python+3': {'title': 'python 3', 'repo_count': '102K'},
    'https://github.com/search?q=world': {'title': 'world', 'repo_count': '1M'},
    'https://github.com/search?q=hello+world': {'title': 'hello world', 'repo_count': '1M'},
    'https://github.com/search?q=i+love+python': {'title': 'i love python', 'repo_count': '517'}
}

# 获取所有需要对比的键（两个字典的键的并集）
all_keys = set(old_state.keys()).union(set(new_state.keys()))

for key in all_keys:
    # 情况1：键只在旧字典中，说明被删除
    if key not in new_state:
        print(f"URL {key} 已被移除")
        continue
    # 情况2：键只在新字典中，说明是新增
    if key not in old_state:
        print(f"新增URL {key}")
        continue
    # 情况3：键在两个字典中，对比内层字段
    old_inner = old_state[key]
    new_inner = new_state[key]
    # 对比title
    if old_inner['title'] != new_inner['title']:
        print(f"URL {key} 的title发生变化：{old_inner['title']} → {new_inner['title']}")
    # 对比repo_count
    if old_inner['repo_count'] != new_inner['repo_count']:
        print(f"URL {key} 的repo_count发生变化：{old_inner['repo_count']} → {new_inner['repo_count']}")

代码说明： #

• 先通过set的并集获取所有需要检查的URL键，避免遗漏新增或删除的条目
• 分三种情况处理每个URL键：删除、新增、存在于两个字典中
• 对存在于两个字典中的键，复用你之前的单层字典对比逻辑，输出具体的变化内容

运行这段代码后，会输出：

URL https://github.com/search?q=python+3 的repo_count发生变化：101K → 102K

内容的提问来源于stack exchange，提问作者PythonNewbie