import json

json_str = '''
{
    "name": "John",
    "age": 30,
    "cars": [
        {"name": "Ford", "models": ["Fiesta", "Focus", "Mustang"]},
        {"name": "BMW", "models": ["320", "X3", "X5"]},
        {"name": "Fiat", "models": ["500", "Panda"]}
    ]
}
'''

# 解析 JSON 字符串為 Python 對象
data = json.loads(json_str)

# 遍歷字典
for key, value in data.items():
    print(f"Key: {key}, Value: {value}")
    
    # 如果值是列表，遍歷列表
    if isinstance(value, list):
        for item in value:
            print(f"  - Item: {item}")
            
            # 如果列表中的元素是字典，遞歸遍歷
            if isinstance(item, dict):
                for nested_key, nested_value in item.items():
                    print(f"    Nested Key: {nested_key}, Nested Value: {nested_value}")

# 注意：對于更復雜的 JSON 結(jié)構(gòu)，可能需要使用遞歸函數(shù)來遍歷所有嵌套的數(shù)據(jù)。

def traverse_json(obj, level=0):
    """
    遞歸遍歷 JSON 數(shù)據(jù)
    :param obj: JSON 對象（可能是字典或列表）
    :param level: 縮進級別（用于美觀輸出）
    """
    if isinstance(obj, dict):
        for key, value in obj.items():
            print(f"{'  ' * level}Key: {key}, Value:")
            traverse_json(value, level + 1)
    elif isinstance(obj, list):
        for i, item in enumerate(obj):
            print(f"{'  ' * level}Item {i}:")
            traverse_json(item, level + 1)
    else:
        print(f"{'  ' * level}Value: {obj}")

# 調(diào)用遞歸函數(shù)遍歷數(shù)據(jù)
traverse_json(data)

def traverse_json_with_none(obj, level=0):
    """
    遞歸遍歷 JSON 數(shù)據(jù)，并處理 None 值
    """
    if isinstance(obj, dict):
        for key, value in obj.items():
            print(f"{'  ' * level}Key: {key}, Value:")
            if value is None:
                print(f"{'  ' * (level + 1)}Value: None")
            else:
                traverse_json_with_none(value, level + 1)
    # ... 其余代碼與上一個示例相同 ...

# 調(diào)用函數(shù)遍歷數(shù)據(jù)
traverse_json_with_none(data)