如何从嵌套的JSON中提取键

def extract_keys(json_data):
    keys = []
    
    def extract(json_obj, parent_key=''):
        if isinstance(json_obj, dict):
            for key in json_obj:
                new_key = parent_key + '.' + key if parent_key else key
                keys.append(new_key)
                extract(json_obj[key], new_key)
        elif isinstance(json_obj, list):
            for i, item in enumerate(json_obj):
                new_key = parent_key + '[' + str(i) + ']' if parent_key else str(i)
                keys.append(new_key)
                extract(item, new_key)
    
    extract(json_data)
    return keys

import json

# 嵌套的JSON数据
json_data = {
    "key1": "value1",
    "key2": {
        "key3": "value3",
        "key4": {
            "key5": "value5"
        }
    },
    "key6": [
        {
            "key7": "value7"
        },
        {
            "key8": "value8"
        }
    ]
}

# 提取键
keys = extract_keys(json_data)

# 打印提取到的键
for key in keys:
    print(key)

key1
key2.key3
key2.key4.key5
key6[0].key7
key6[1].key8