`if` logical judgment tag supports which conditional judgment operations in AnQiCMS template?

As an experienced website operations expert, I know that a powerful and flexible template system is crucial for the effective presentation of website content.AnQiCMS (AnQi Content Management System) provides great convenience for our content operation with its high efficiency based on the Go language and the grammar features borrowed from the Django template engine.In AnQiCMS template development, proficiently using logical judgment tags is the key to dynamic content display and enhancing user experience.ifLogical judgment label supported conditions.

Unlock AnQiCMS template logic judgment: In-depth analysis.ifThe mystery of tags

In the template world of AnQiCMS,ifLabels play the role of a "decision-maker".It allows us to flexibly control the display and hiding of content based on different conditions, thus achieving more interactive and personalized page effects.ifThe clever use of tags.

AnQiCMSifThe label syntax style is very similar to the Django template engine we are familiar with, it starts with{% if 条件 %}at the beginning, followed by{% endif %}and can be nested in the middle{% elif 其他条件 %}(which is equivalent to else if) and{% else %}A clause, constitutes a complete conditional judgment structure.

{% if 条件 %}
    <!-- 条件为真时显示的内容 -->
{% elif 另一个条件 %}
    <!-- 当第一个条件为假，但第二个条件为真时显示的内容 -->
{% else %}
    <!-- 所有条件都为假时显示的内容 -->
{% endif %}

Next, let's go through in detail what kinds of flexible and variable operations this 'condition' part supports.

1. True and False Evaluation: Perceiving the 'Existence' and 'Non-existence' of Data

In many programming languages, certain values are automatically evaluated as "true" (Truthy) or "false" (Falsy). AnQiCMS templateifLabels also follow this principle. Generally, the following situations are considered to be 'false values':

• nilornothing: indicates that the variable does not exist or is empty.
• 0: zero.
• Empty string"".
• An empty array, empty slice (slice), or empty map.

Except for these, all non-empty, non-zero,nilThe value, will be evaluated as "true". This allows us to very succinctly judge whether a variable has content, whether a list is empty, and so on.

Example:

{# 判断文档标题是否存在或非空 #}
{% if archive.Title %}
    <h1>{{ archive.Title }}</h1>
{% else %}
    <h1>[无标题]</h1>
{% endif %}

{# 判断分类列表是否为空 #}
{% if categories %}
    <ul class="category-list">
        {% for category in categories %}
            <li><a href="{{ category.Link }}">{{ category.Title }}</a></li>
        {% endfor %}
    </ul>
{% else %}
    <p>暂无分类信息。</p>
{% endif %}

2. English for Equal and Unequal Judgment: Exact Match Data

The most common judgment is the comparison of values.ifTags support standard English for equal (==) and English for unequal (!=）Operator, used to compare values of numbers, strings, and other comparable types.

Example:

{# 判断当前文档ID是否为特定值，例如用于展示特定内容块 #}
{% if archive.Id == 10 %}
    <div class="special-promo">
        <p>这是ID为10的特别推荐内容。</p>
    </div>
{% elif archive.Id != 5 %}
    <p>这不是ID为5的文档。</p>
{% endif %}

{# 判断用户组名称 #}
{% if user.GroupName == "VIP" %}
    <p>欢迎尊贵的VIP用户！</p>
{% endif %}

3. Numeric comparison judgment: size and range are all under control.

For numeric data types, we can perform various size comparisons, such as greater than, less than, greater than or equal to, and less than or equal to.These operators are very useful in scenarios such as handling product prices, article views, and user points.

Supported operators:

• Greater than:>
• Less than:<
• Greater than or equal to:>=
• Less than or equal to:<=

Example:

{# 根据文章浏览量显示不同样式 #}
{% if archive.Views > 1000 %}
    <span class="badge badge-hot">🔥 热点文章</span>
{% elif archive.Views >= 500 %}
    <span class="badge badge-trending">📈 流行趋势</span>
{% else %}
    <span class="badge">普通文章</span>
{% endif %}

{# 判断产品库存是否充足 #}
{% if product.Stock <= 0 %}
    <span class="out-of-stock">已售罄</span>
{% else %}
    <span class="in-stock">库存充足 (剩余{{ product.Stock }}件)</span>
{% endif %}

4. Logical combination judgment: Build complex conditions

A single condition often cannot meet the needs of complex business logic. AnQiCMS'sifThe label supports using logical operators to combine multiple conditions, thereby creating more refined judgments.

Supported logical operators:

• AND:andor&&。When all conditions are true, the result is true.
• 或（OR）:oror||。When any condition is true, the result is true.
• 非（NOT）:notor!。Reverse the truth value of the condition.

When combining conditions, it is recommended to use parentheses()to clarify the logical priority and improve the readability of the code.

Example:

{# 判断文章是否为头条推荐且浏览量超过2000 #}
{% if archive.Flag == "h" and archive.Views > 2000 %}
    <p class="featured-headline">【今日头条】此文不可错过！</p>
{% endif %}

{# 判断用户是否为VIP会员或处于试用期 #}
{% if user.IsVIP or user.IsTrialPeriod %}
    <p>您拥有高级功能访问权限。</p>
{% else %}
    <p>升级会员以解锁更多功能。</p>
{% endif %}

{# 判断分类ID不等于1且不是产品模型 #}
{% if archive.CategoryId != 1 and not (archive.ModuleId == 2) %}
    <p>这是一个非默认分类且非产品模型的文档。</p>
{% endif %}

5. Member Relationship Judgment: Check element affiliation

inThe operator is a very convenient feature that allows us to check if an element exists in a set (such as a string, array, or the keys of a map).

Example:

{# 判断当前用户所属组是否在特定VIP组列表中 #}
{% if user.GroupName in ["钻石会员", "铂金会员"] %}
    <p>您是尊贵的{{ user.GroupName }}，享有专属服务！</p>
{% endif %}

{# 检查文章的Flag属性中是否包含"c"（推荐）标志 #}
{% if "c" in archive.Flag %}
    <p>这篇文章被推荐了。</p>
{% endif %}

Through the above conditions judgment operation, AnQiCMS'sifTags can help us achieve powerful logic control at the template level. Whether it is simple content display/hide, or complex personalized display based on user role, data status,ifTags are essential tools for building dynamic and intelligent websites.Mastery of these judgment methods will greatly enhance your content operation and template development efficiency on the AnQiCMS platform.

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Common Questions (FAQ)

Q1:ifLabel can directly determine whether a string variable is empty? A1:Yes, it can be done completely. In the template engine of AnQiCMS,""）would be automatically evaluated as a "falsy" value. Therefore, you do not need to perform an explicitarchive.Title == ""such judgment, just use{% if archive.Title %}to determineTitlewhether a variable has content. IfTitleIs an empty string, the condition is false; ifTitlethere is any non-empty character, the condition is true.

Q2:ifDoes the label support regular expression (Regular Expression) for complex string matching judgment? A2:According to AnQiCMS template syntax design,ifThe logic judgment tag itself does not directly support regular expressions as conditional judgment operations. It is mainly used for equality/not equality based on variable values, numbers, and strings