为json的不同嵌套级别提取不同的键集

def extract_keys(json_obj, level=0):
    keys = set()
    if isinstance(json_obj, dict):
        for key, value in json_obj.items():
            keys.add(key)
            if isinstance(value, (dict, list)):
                keys.update(extract_keys(value, level+1))
    elif isinstance(json_obj, list):
        for item in json_obj:
            keys.update(extract_keys(item, level+1))
    return keys

import json

# 示例JSON对象
json_str = '''
{
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "country": "USA"
  },
  "hobbies": ["reading", "music", "sports"],
  "friends": [
    {
      "name": "Alice",
      "age": 28
    },
    {
      "name": "Bob",
      "age": 32
    }
  ]
}
'''

# 将JSON字符串解析为Python对象
json_obj = json.loads(json_str)

# 提取键集
keys = extract_keys(json_obj)

# 打印结果
for key in keys:
    print(key)

name
age
address
street
city
country
hobbies
0
1
name
age