How to judge if a specific element is contained in the array after `split` filter is used?

During content management and template development, we often encounter the need to process a string and then determine whether the processed result contains specific information.For example, a document may have multiple tags or categories, and this information is usually stored as a string connected by separators such as commas.When determining the display style of the page based on these tags or categories, it is particularly important to judge whether it contains a specific element.

AnQiCMS provides powerful template tags and filters to make this operation simple and intuitive. This article will delve into how to utilizesplitfilters to split strings and combinecontainorindexFilter to determine whether a cut list contains a specific element.

Core Function Analysis:splitFilter

Firstly, let's get to knowsplitFilter.Its main function is to split a string into a list using a specified delimiter (commonly referred to as an array or slice in programming context).This is like us splitting a long string of words separated by commas into individual words.

The basic usage is as follows:

{{ 你的字符串 | split:"分隔符" }}

For example, if your article tags are stored in a comma-separated string, we can use it like this.splitFilter:

{% set tags_string = "AnQiCMS,模板制作,SEO优化,内容营销" %}
{% set tag_list = tags_string | split:"," %}

{# 原始字符串：AnQiCMS,模板制作,SEO优化,内容营销 #}
<span>原始字符串：{{ tags_string }}</span>
{# 切割后的列表（为了方便显示，我们用join过滤器再次连接）：AnQiCMS | 模板制作 | SEO优化 | 内容营销 #}
<span>切割后的列表：{{ tag_list | join:" | " }}</span>

Here,tags_stringThis is the original string we are processing.split:","The result is cut with a comma as the delimiter.tag_listNow it is a list containing four elements, each of which is a tag.

Determine whether the element exists:containThe magic of filters

When you already have a list that has beensplitcut by a filter, how can you efficiently judge whether this list contains the element you want? At this point,containThe filter comes into play.containThe filter can determine whether a string, list, map, or struct contains a specific keyword and directly returns a boolean value.trueorfalse).

containThe basic usage of the filter is as follows:

{{ 你的列表或字符串 | contain:"目标元素" }}

Now, we willsplitandcontainCombining filters to determine if the split list contains the label 'SEO optimization':

{% set tags_string = "AnQiCMS,模板制作,SEO优化,内容营销" %}
{% set tag_list = tags_string | split:"," %} {# 将字符串切割成列表 #}

{% set has_seo_tag = tag_list | contain:"SEO优化" %} {# 判断列表中是否包含“SEO优化” #}

{% if has_seo_tag %}
    <span>这个内容包含了“SEO优化”标签。</span>
{% else %}
    <span>这个内容不包含“SEO优化”标签。</span>
{% endif %}

In the above code, we first obtainsplittotags_stringConverted totag_list.tag_list | contain:"SEO优化"Check if the element 'SEO optimization' exists in this list, and assign the result tohas_seo_tagthe variable. Finally, use aifstatement to determinehas_seo_tagThe boolean value to display different content. This method is concise and clear, very suitable for conditional judgments.

Another idea:indexAuxiliary judgment for the filter

ExceptcontainFilter returns a boolean value directly, in addition, we can also useindexfilter to indirectly judge.indexThe filter will search for the target element in a string or list and return the index of the first occurrence if found, or return nothing if not found.-1.

indexThe basic usage of the filter is as follows:

{{ 你的列表或字符串 | index:"目标元素" }}

UtilizeindexThe method to filter a list to check if it contains a specific element is: first get the position of the target element, then judge if this position is not equal to-1(i.e., not not found).

{% set tags_string = "AnQiCMS,模板制作,SEO优化,内容营销" %}
{% set tag_list = tags_string | split:"," %} {# 将字符串切割成列表 #}

{% set seo_tag_position = tag_list | index:"SEO优化" %} {# 获取“SEO优化”在列表中的位置 #}

{% if seo_tag_position != -1 %}
    <span>“SEO优化”标签在列表中的位置是：{{ seo_tag_position }}。</span>
{% else %}
    <span>这个内容不包含“SEO优化”标签。</span>
{% endif %}

This method is similar tocontainThe filter effect is the same, but in some cases where it is necessary to know the specific position of the elements,indexthe filter will have more advantages. If it is only a matter of determining whether it exists,containthe filter will be more direct and recommended.

Scene application example

Consider a more practical scenario: You are designing a product detail page template, where a product may have multiple features, which are stored as strings, such as"防水,防震,高清摄像头"You wish to display a special icon on the page if the product has the "waterproof" feature.

{% set product_features_string = "防水,防震,高清摄像头" %}
{% set feature_list = product_features_string | split:"," %}

{# 判断是否包含“防水”特性 #}
{% if feature_list | contain:"防水" %}
    <span class="feature-icon feature-waterproof"></span>
    <p>该产品支持防水功能。</p>
{% endif %}

{# 判断是否包含“防震”特性 #}
{% if feature_list | contain:"防震" %}
    <span class="feature-icon feature-shockproof"></span>
    <p>该产品具备防震设计。</p>
{% endif %}

{# 循环显示所有特性 #}
<ul class="product-features-list">
    {% for feature in feature_list %}
        <li>{{ feature }}</li>
    {% endfor %}
</ul>

Through such applications, we can flexibly control the display logic of the front-end pages based on the content characteristics without changing the way the backend data storage is done, greatly enhancing the dynamics and maintainability of the template.

Summary

MastersplitThe ability of the filter to split strings into lists and combine themcontainorindexThe filter's ability to judge whether a specific element exists in a list, which is a very practical skill in the development of AnQiCMS templates.containThe filter provides an intuitive boolean return value, making it the preferred choice for determining the existence of elements; andindexThe filter is used when it is necessary to obtain the specific position of an element.Apply these filters flexibly to your templates, which will enable you to process dynamic content more efficiently and meet diverse display requirements.

---

Common Questions (FAQ)

Q1:splitWhat happens when the separator itself is part of the string being split by the filter? For example, using,split"A,B,,C".

A1: WhensplitThe filter creates an empty string element between consecutive delimiters. For example,"A,B,,C" | split:","the result will be["A", "B", "", "C"]which includes an empty string. When usingcontainorindexPerform subsequent judgment, be aware of the existence of this empty string.

**Q2: How do I