Python提取嵌套的JSON值

import json

def extract_nested_value(json_data, target_key):
    if isinstance(json_data, dict):
        for key, value in json_data.items():
            if key == target_key:
                return value
            elif isinstance(value, (dict, list)):
                result = extract_nested_value(value, target_key)
                if result is not None:
                    return result
    elif isinstance(json_data, list):
        for item in json_data:
            result = extract_nested_value(item, target_key)
            if result is not None:
                return result
    
    return None

# 示例JSON数据
json_str = '''
{
    "name": "John",
    "age": 30,
    "address": {
        "city": "New York",
        "country": "USA"
    },
    "friends": [
        {
            "name": "Alice",
            "age": 28
        },
        {
            "name": "Bob",
            "age": 32
        }
    ]
}
'''

# 解析JSON数据
data = json.loads(json_str)

# 提取嵌套的JSON值
name = extract_nested_value(data, "name")
city = extract_nested_value(data, "address.city")
friend_age = extract_nested_value(data, "friends.0.age")

# 输出结果
print(name)  # 输出: John
print(city)  # 输出: New York
print(friend_age)  # 输出: 28