django for-loop 只顯示最后一次迭代

Question

我正在構建圖書推薦 Django 應用程序。 我已經完成了我的機器學習模型的集成，但問題是它從我使用的 csv 文件中獲取數據，而不是從我的數據庫中獲取數據。 我在顯示推薦書籍的標題時沒有問題，但我想讓用戶查看所述書籍的詳細信息頁面。 話雖如此，我需要從我的Book模型中獲取推薦書籍的 ID。

我是 Django 的新手，所以如果我的代碼混亂請見諒。

這是我的views.py的摘錄：

def s_detail(request, book_id): #student paper detail
    cosine_sim = joblib.load('cosine_sim-v5.pkl') #load the ml model 
    data = pd.read_csv('try.csv', sep=',', encoding='utf-8')
    try:
        book = Book.objects.get(pk=book_id)
        fav = True 
        if book.favorites.filter(id=request.user.id).exists():
            fav=False
    
        def recommendations(book_id,n, cosine_sim = cosine_sim):
            recommended_books = []
            idx = book_id
            score_series = pd.Series(cosine_sim[idx]).sort_values(ascending = False)
            top_n_indexes = list(score_series.iloc[1:n+1].index)
            for i in top_n_indexes:
                recommended_books.append(list(data.index)[i]) # data.index for book_id column
            return recommended_books

        recommend = recommendations(book_id, 3) 
        for i in recommend: 
            new = Book.objects.filter(id=i) #to get the Book id from the model 
            print(new) #just to check if it's working

    except Book.DoesNotExist: 
        raise Http404("Title does not exist")    
    return render (request, 'books/s_detail.html', {'book':book, 'fav':fav, 'recommend':recommend, 'new':new}) 

在我的模板中：

{% for book in new %}
    <div class="card">     
      <img src="/books/media/{{book.book_image}}" alt="bookimage"><br>
        <div class="browse-content">
            <b>Title:</b> <a href="{% url 's_detail' book.id %}"> {{book.book_title}} </a><br>
            <div class="eye">
                <i class="fa-solid fa-eye"></i> Views
            </div>
        </div>
    </div>
{% endfor %}

根據終端中的打印輸出，迭代工作正常

[22/Dec/2022 10:27:42] "GET /books/s_browse HTTP/1.1" 200 27157
<QuerySet [<Book: Radioprotective Potential of Leaf Extract of Sapinit (Rubus rosifolius) On the Sperm Count and Sperm Morphology of y-Irradiated Mice (Mus musculus)>]>
<QuerySet [<Book: Analysis of Cytotoxic Activities of Select Plant Extracts against A549 - Lung Adenocarcinoma Cell Line>]>
<QuerySet [<Book: Inventory of Epiphytes on the Walls of Intramuros, Manila>]>

但只顯示模板中的最后一次迭代

我覺得我需要將值存儲在某個地方，但我不知道如何存儲。

Answer 1

您正在for循環中用大小為 1 的新QuerySet覆蓋new變量。 嘗試替換以下內容：

recommend = recommendations(book_id, 3) 
for i in recommend: 
    new = Book.objects.filter(id=i) #to get the Book id from the model 
    print(new) #just to check if it's working

有了這個：

recommend = recommendations(book_id, 3) 
new = Book.objects.filter(id__in=recommend)
print(new)

這將獲取具有recommend列表中存在的id值的所有Book實例。