TWIG's tests learning_PHP tutorial

Making logical judgments. Currently supported are

divisibleby null even odd sameas constant defined empty

divisibleby
Check if it is divisible

{% if loop.index is divisibleby(3) %}
...
{% endif %}
{% if loop.index is divisibleby(3) %}
...
{% endif %}

null
{{ var is null }}
{{ var is null }}

even
Whether the variable is even {{ var is even }}
{{ var is even }}

odd
Whether the variable is an odd number

{{ var is odd }} <br>
<pre name="code" class="html">{{ var is odd }}
<p> </p>
<p> </p>
<p>sameas<br>
Check if the addresses of variables are the same</p>
<p>{% if foo.attribute is sameas(false) %} <br>
The foo attribute really is the ``false`` PHP value <br>
{% endif %} <br>
{% if foo.attribute is sameas(false) %}<br>
The foo attribute really is the ``false`` PHP value<br>
{% endif %}</p>
<p> </p>
<p>constant<br>
Check if the values ​​of variables are the same</p>
<p>{% if post.status is constant('Post::PUBLISHED') %} <br>
The status attribute is exactly the same as Post::PUBLISHED <br>
{% endif %} <br>
{% if post.status is constant('Post::PUBLISHED') %}<br>
The status attribute is exactly the same as Post::PUBLISHED<br>
{% endif %}</p>
<p> </p>
<p>defined<br>
Test whether the variable is defined </p>
<p>{# defined works with variable names #} <br>
{% if foo is defined %} <br>
... <br>
{% endif %} <br>
<br>
{# and attributes on variables names #} <br>
{% if foo.bar is defined %} <br>
... <br>
{% endif %} <br>
<br>
{% if foo['bar'] is defined %} <br>
... <br>
{% endif %} <br>
{# defined works with variable names #}<br>
{% if foo is defined %}<br>
...<br>
{% endif %}</p>
<p>{# and attributes on variables names #}<br>
{% if foo.bar is defined %}<br>
...<br>
{% endif %}</p>
<p>{% if foo['bar'] is defined %}<br>
...<br>
{% endif %}</p>
<p> </p>
<p>empty<br>
Test whether the variable is empty. Empty means: the variable has been defined, but its value is null false or an empty string <br>
{# evaluates to true if the foo variable is null, false, or the empty string #} <br>
{% if foo is empty %} <br>
... <br>
{% endif %} <br>
<br>
Excerpted from jiaochangyun’s column</p>

<p align="left"></p><div style="display:none;">
<span id="url" itemprop="url">http://www.bkjia.com/PHPjc/478456.html</span><span id="indexUrl" itemprop="indexUrl">www.bkjia.com</span><span id="isOriginal" itemprop="isOriginal">true</span><span id="isBasedOnUrl" itemprop="isBasedOnUrl">http: //www.bkjia.com/PHPjc/478456.html</span><span id="genre" itemprop="genre">TechArticle</span><span id="description" itemprop="description">makes logical judgments. Currently supported are divisibleby null even odd same as constant defined empty divisibleby Check whether it can be divisible {% if loop.index is divisibleby(3) %} ... {% en...</span>
</div>
<div class="art_confoot"></div>