Django - 如何在模板“for"循环中进行元组解包

2022-01-19 00:00:00 python django tuples iterable-unpacking templates

问题描述

在我的views.py中，我正在构建一个双元组列表，其中元组中的第二项是另一个列表，如下所示:

In my views.py, I'm building a list of two-tuples, where the second item in the tuple is another list, like this:

[ Product_Type_1, [ product_1, product_2 ],
  Product_Type_2, [ product_3, product_4 ]]

在普通的旧 Python 中，我可以像这样迭代列表:

In plain old Python, I could iteration the list like this:

for product_type, products in list:
    print product_type
    for product in products:
        print product

我似乎无法在我的 Django 模板中做同样的事情:

I can't seem to do the same thing in my Django template:

{% for product_type, products in product_list %}
    print product_type
    {% for product in products %}
        print product
    {% endfor %}
{% endfor %}

我从 Django 收到此错误:

I get this error from Django:

渲染时遇到异常:zip 参数 #2 必须支持迭代

当然，模板中有一些 HTML 标记，而不是打印语句.Django 模板语言不支持元组解包吗?还是我以错误的方式解决这个问题?我要做的只是显示一个简单的对象层次结构 - 有几种产品类型，每种都有几个产品(在 models.py 中，Product 有一个 Product_type 的外键，一个简单的一对多关系).

Of course, there is some HTML markup in the template, not print statements. Is tuple unpacking not supported in the Django template language? Or am I going about this the wrong way? All I am trying to do is display a simple hierarchy of objects - there are several product types, each with several products (in models.py, Product has a foreign key to Product_type, a simple one-to-many relationship).

显然，我对 Django 还是很陌生，因此我们将不胜感激.

Obviously, I am quite new to Django, so any input would be appreciated.

解决方案

最好像{note the '(' and ')' can be exchangely for '[' and ']' 这样构建数据，一个用于元组，一个用于列表}

it would be best if you construct your data like {note the '(' and ')' can be exchanged for '[' and ']' repectively, one being for tuples, one for lists}

[ (Product_Type_1, ( product_1, product_2 )),
   (Product_Type_2, ( product_3, product_4 )) ]

并让模板执行此操作:

{% for product_type, products in product_type_list %}
    {{ product_type }}
    {% for product in products %}
        {{ product }}
    {% endfor %}
{% endfor %}

元组/列表在 for 循环中解包的方式基于列表迭代器返回的项目.每次迭代只返回一项.第一次循环，Product_Type_1，第二次你的产品列表......

the way tuples/lists are unpacked in for loops is based on the item returned by the list iterator. each iteration only one item was returned. the first time around the loop, Product_Type_1, the second your list of products...

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