从液体中获取数组中的下一个和上一个元素 [英] Get next and previous elements out of an array in liquid

问题描述

简短版本:

我想在液体模板中的数字上加1，然后将结果用作数组索引.

I want to add 1 to a number in a liquid template and use the result as an array index.

{% capture plus_one %}{{ 0 | plus: 1 }}{% endcapture %}
<div>-Value of plus_one: {{plus_one}}</div>
<div>-This works: {{site.posts[1].title}}</div>
<div>-This doesn't: {{site.posts[plus_one].title}}</div>

结果:

-Value of plus_one: 1
-This works: The Zone
-This doesn't:

---

长版:

---

Long version:

我正在使用Jekyll，没有任何插件.我想给当前帖子一个链接，指向下一个属于同一类别的帖子. (该类别在此代码中被硬编码为新闻".)

I'm using Jekyll, with no plugins. I want to give the current post a link to the next post that is in the same category. (The category is hardcoded to 'journal' in this code.)

我的代码遍历category数组中的所有帖子，寻找当前帖子.找到后，我尝试获取类别数组中的下一篇文章.

My code loops over all posts in the category array, looking for the current post. When it is found, I try to grab the next post in the category array.

{% for num in (0..site.categories.journal.size) %}
    {% assign page2 = site.categories.journal[num] %}
        {% if page2.title == page.title and page2.date == page.date %}
            {% capture plus_one %}{{ num | plus: 1 }}{% endcapture %}
        {% endif %}
{% endfor %}

<div>value of plus_one: {{plus_one}}</div>
<div>This doesn't work: {{site.categories.journal[plus_one].title}}</div>
<div>This does: {{site.categories.journal[1].title}}</div>

结果:

<div>value of plus_one: 1</div>
<div>This doesn't work: </div>
<div>This does: A Blog Post Title</div>

我猜我的变量'plus_one'的值被视为字符串而不是数字.

I guess the value of my variable 'plus_one' is being treated as a string instead of a number.

有什么办法可以将其转换为数字?

Is there any way to convert it to a number?

还是有另一种方法可以实现我想要做的事情?

Or is there another way to achieve what I'm trying to do?

推荐答案

{% for category in site.categories %}
    {% assign catg_name = category.first %}
    {% if catg_name == page.category %}
        {% assign catg_posts = category.last %}
    {% endif %}
{% endfor %}
{% for post in catg_posts %}
    {% if post.title == page.title %}
        {% unless forloop.last %}
            {% assign next = catg_posts[forloop.index] %}
            <li class="previous">
            <a href="{{ site.baseurl }}{{ next.url }}">&larr;{{ next.title }}</a>
            </li>
        {% endunless %}
        {% unless forloop.first %}
            <li class="next">
            <a href="{{ site.baseurl }}{{ prev.url }}">{{ prev.title }}&rarr;</a>
            </li>
        {% endunless %}
    {% endif %}
    {% assign prev = post %}
{% endfor %}

正如您所提到的，您可以保存并使用上一个迭代值作为上一个帖子链接(在我的情况下，因为我不希望默认的最新顺序，所以我将其用作下一个帖子链接).对于下一个数组元素，可以使用forloop.index.这是for循环的从1开始的索引，将为您提供从0开始的数组的下一项.

As you have mentioned you can save and use the previous iteration value for the previous post link( in my case I use it as the next post link since I don't want the default newest-first order ). For the next array element you can use forloop.index. This is the 1-based index of the for loop and will give you the next item of a zero-based array.

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