Python中获取字典数组内嵌套字典遇TypeError，求解决方案

数据结构示例 #

返回的Topics列表结构如下：

[
    {
        "Topic Id": null,
        "Topic Name": null,
        "Topic Title": null,
        "Topic Summary": null,
        "Topic Matching Information": null,
        "Actions": {
            "actions": [
                {
                    "action_id": "1",
                    "action_title": "Review Video",
                    "action_summary": "Watch the video",
                    "assigned_to": "nomail@email.com",
                    "due_date": "2024-05-24",
                    "action_attachments": [],
                    "action_owner": "Rumble",
                    "action_status": "Open"
                },
                {
                    "action_id": "2",
                    "action_title": "Review Barker Dam Annual Spill",
                    "action_summary": "Read the email about Barker Dam’s Annual Spill Expected in Coming Days.",
                    "assigned_to": "noemail@email.com",
                    "due_date": "2024-05-24",
                    "action_attachments": [],
                    "action_owner": "Your Lower Chautauqua neighbors",
                    "action_status": "Open"
                }
            ]
        }
    },
    {
        "Topic Id": "new_topic_001",
        "Topic Name": "G-File Notification",
        "Topic Title": "G-File Update Notification",
        "Topic Summary": "Notification about the absence of today's G-File and an update on upcoming content.",
        "Topic Matching Information": {
            "subject": "About Today’s G-File",
            "sender": "",
            "recipient": "",
            "keywords": [
                "G-File",
                "newsletter"
            ]
        },
        "Actions": {
            "actions": [
                {
                    "action_id": "1",
                    "action_title": "Review Today's G-File",
                    "action_summary": "John Smith needs to review the G-File sent on 2024-05-17.",
                    "assigned_to": "John Smith",
                    "due_date": "2024-05-18",
                    "action_attachments": [],
                    "action_owner": "John Smith",
                    "action_status": "None"
                }
            ]
        }
    }
]

尝试的代码 #

最初尝试的遍历代码：

for this_topic in topics:
     for this_action in this_topic["Actions"]["actions"]:
         # 处理逻辑
         pass

还试过以下错误写法：

• ["Action"].get("actions")（字段名拼写错误，少了末尾的s）
• ["Action"][0]（同样拼写错误，且错误将字段视为列表）

错误信息 #

运行代码后抛出如下错误：

TypeError: list indices must be integers or slices, not str

问题分析 #

报错提示列表不能使用字符串作为索引，说明在执行this_topic["Actions"]["actions"]时，其中某一层是列表类型而非字典：

1. 可能存在部分Topic的Actions字段不是字典，而是列表（比如接口返回数据格式不一致，部分条目将Actions封装为数组）
2. 拼写错误：比如尝试["Action"]而非正确的["Actions"]，导致取到None或错误类型，后续操作引发异常

解决方法 #

方法1：安全取值（推荐） #

使用dict.get()方法避免KeyError，同时默认返回空容器，确保遍历不会中断：

for this_topic in topics:
    # 安全获取Actions字典，无此字段则返回空字典
    actions_container = this_topic.get("Actions", {})
    # 安全获取actions列表，无此字段则返回空列表
    actions_list = actions_container.get("actions", [])
    for this_action in actions_list:
        # 处理每个action的逻辑
        print(this_action["action_title"])

方法2：类型检查兼容异常格式 #

如果存在部分Topic的Actions是列表的情况，增加类型判断兼容这种异常格式：

for this_topic in topics:
    actions_data = this_topic.get("Actions")
    # 处理Actions是字典的正常情况
    if isinstance(actions_data, dict):
        actions_list = actions_data.get("actions", [])
        for this_action in actions_list:
            # 处理逻辑
            pass
    # 处理Actions是列表的异常情况
    elif isinstance(actions_data, list):
        for item in actions_data:
            actions_list = item.get("actions", [])
            for this_action in actions_list:
                # 处理逻辑
                pass
    # 跳过无Actions或格式错误的条目
    else:
        continue

内容的提问来源于stack exchange，提问作者user23640624