Python迭代生成嵌套字典时数据被覆盖问题求助

我正尝试将符合条件的图书数据从CSV文件写入JSON文件，目标结构是顶级键为bookID、值为包含info和ratings嵌套字典的结构。遍历字典列表jsonArray时，发现顶级的bookID能正确切换，但每个bookID对应的info和ratings内容始终被数据集的最后一条条目覆盖。我确认循环中info_dict和rating_dict能生成单条图书的正确数据，但它们在json_dict中被后续迭代的内容覆盖。bookID是唯一的，不清楚如何避免这种覆盖问题。

当前代码 #

def retrieve_popular_books(csv_in, json_out):
    jsonArray = []
    json_dict = {}
    info_list = []
    rating_list = []
    book_id = []
    info_dict = {}
    rating_dict = {}

    with open(csv_in, newline='') as csv_file:
        csv_dict_reader = csv.DictReader(csv_file)

        for row in csv_dict_reader:
            average_rating = float(row["average_rating"])
            num_pages = int(row["num_pages"])
            ratings_count = int(row["ratings_count"])
            if average_rating > 4.50 and num_pages > 50 and ratings_count > 1000:
                jsonArray.append(row)
        
        for i in jsonArray:
            book_id = i['bookID']
            json_dict[book_id] = {}
            for k,v in i.items():
                if k != "bookID" and k!= "average_rating" and k!="ratings_count" and k!=     "text_reviews_count":
                    info_list.append({k:v})
                if k== "average_rating" or k=="ratings_count" or k== "text_reviews_count":
                    rating_list.append({k:v})
            for i in info_list:
                for k,v in i.items():
                    info_dict[k] = v
                    json_dict[book_id]["info"] = info_dict
            for i in rating_list:
                for k,v in i.items():
                    rating_dict[k] = v
                    json_dict[book_id]["ratings"] = rating_dict
   
    with open(json_out, 'w') as jsonf:
        json.dump(json_dict, jsonf, indent=4)

retrieve_popular_books('books_data/books_v2.csv', 'books_data/books_v2_copy.json')

当前错误结果（部分） #

{
    "863f3fd8-b4f5-43b8-8ec1-eb870faa334e": {
        "info": {
            "title": "Fullmetal Alchemist  Vol. 6 (Fullmetal Alchemist  #6)",
            "authors": "Hiromu Arakawa/Akira Watanabe",
            "isbn": "1421503190",
            "isbn13": "9781421503196",
            "language_code": "eng",
            "num_pages": "200",
            "publication_date": "3/21/2006",
            "publisher": "VIZ Media LLC"
        },
        "ratings": {
            "average_rating": "4.58",
            "ratings_count": "10052",
            "text_reviews_count": "201"
        }
    },
    "b343cec8-66dc-470a-8efe-47858e37aab5": {
        "info": {
            "title": "Fullmetal Alchemist  Vol. 6 (Fullmetal Alchemist  #6)",
            "authors": "Hiromu Arakawa/Akira Watanabe",
            "isbn": "1421503190",
            "isbn13": "9781421503196",
            "language_code": "eng",
            "num_pages": "200",
            "publication_date": "3/21/2006",
            "publisher": "VIZ Media LLC"
        },
        "ratings": {
            "average_rating": "4.58",
            "ratings_count": "10052",
            "text_reviews_count": "201"
        }
    }
}

问题原因 #

核心问题是**info_dict、rating_dict、info_list、rating_list这些容器是在循环外部初始化的**：

• 每次处理新图书时，你只是往同一个info_list/rating_list里追加数据，修改同一个info_dict/rating_dict的键值对
• Python中字典是引用类型，所有bookID对应的"info"和"ratings"都指向同一个字典对象，后续修改会覆盖之前的内容，最终所有条目都显示最后一次循环的结果

修正方案 #

把字典和列表的初始化移到遍历单本图书的循环内部，确保每本书都有独立的容器实例，同时可以简化逻辑，直接构建目标字典：

def retrieve_popular_books(csv_in, json_out):
    json_dict = {}

    with open(csv_in, newline='') as csv_file:
        csv_dict_reader = csv.DictReader(csv_file)

        for row in csv_dict_reader:
            # 过滤条件
            average_rating = float(row["average_rating"])
            num_pages = int(row["num_pages"])
            ratings_count = int(row["ratings_count"])
            if average_rating > 4.50 and num_pages > 50 and ratings_count > 1000:
                book_id = row['bookID']
                # 为当前图书创建独立的info和ratings字典
                info_dict = {}
                rating_dict = {}
                # 拆分数据到对应字典
                for k, v in row.items():
                    if k == "bookID":
                        continue
                    elif k in ["average_rating", "ratings_count", "text_reviews_count"]:
                        rating_dict[k] = v
                    else:
                        info_dict[k] = v
                # 加入最终字典
                json_dict[book_id] = {
                    "info": info_dict,
                    "ratings": rating_dict
                }
   
    with open(json_out, 'w') as jsonf:
        json.dump(json_dict, jsonf, indent=4)

retrieve_popular_books('books_data/books_v2.csv', 'books_data/books_v2_copy.json')

修正说明 #

1. 移除了冗余的jsonArray、info_list、rating_list，直接在读取CSV行时处理，节省内存
2. 每处理一本符合条件的图书，就新建info_dict和rating_dict，确保每个bookID对应独立的字典实例
3. 简化了键值对的拆分逻辑，直接通过判断键名分配到对应字典
4. 避免了引用类型导致的覆盖问题，每个图书的info和ratings都是独立的对象

内容的提问来源于stack exchange，提问作者Nathan