如何在显示json数据时删除未定义的数据

import json

def remove_undefined_data(json_data):
    # 解析 JSON 数据
    data = json.loads(json_data)

    # 遍历数据
    if isinstance(data, dict):
        for key in list(data.keys()):
            # 删除未定义的属性
            if data[key] is None:
                del data[key]
            # 递归处理嵌套的 JSON 对象或数组
            elif isinstance(data[key], (dict, list)):
                remove_undefined_data(json.dumps(data[key]))
    elif isinstance(data, list):
        for i in range(len(data)):
            # 删除未定义的元素
            if data[i] is None:
                del data[i]
            # 递归处理嵌套的 JSON 对象或数组
            elif isinstance(data[i], (dict, list)):
                remove_undefined_data(json.dumps(data[i]))

    # 生成新的 JSON 数据
    new_json_data = json.dumps(data)
    return new_json_data

# 示例数据
json_data = '''
{
  "name": "John",
  "age": null,
  "address": {
    "street": "123 Main St",
    "city": null
  },
  "hobbies": ["reading", null, "swimming"]
}
'''

# 删除未定义的数据
new_json_data = remove_undefined_data(json_data)
print(new_json_data)