The clever use of Countable in ThinkPHP containers

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This article will explain an unpopular knowledge point that you will not understand at all if you don’t look at the source code, that is the use of countTable.

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6. Container Container Class Analysis: Clever Use of Countable

About Countable I have never thought about whether to write the content in the form of an article and show it to everyone, but when I read the source code later, a large number of Countable applications appeared.

In order for everyone to understand every technical point, Kaka still writes it out.

This knowledge point is just to show you how to use it. The relationship with count will be mentioned later in the article.

In the file thinkphp/library/think/Container.php, you can directly see that the Countable interface is used and implemented!

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Coming to the Countable interface, we can only see one method which is count() .

According to the comment Count elements of an object in the code, we can understand that this interface is to count the elements of the object

In the process of reading the source code, we need to read its comments first. Even if you don’t know English, there is translation software! Will provide you with a better understanding.

Let’s learn more about it according to the instructions in the PHP documentation.

The document states that when you execute the count() method, it is equivalent to executing the above abstract public Countable::count (void) : intabstract method.

Practical Case

If you talk but don’t do it, everything will come to nothing; if you talk and do it, you will succeed immediately. Start directly

Create a new filekaka/container/countableTest.php, and add the following content

Then in the fileapplication/index/controller/ Container.php Learn to use Countable.

Pay attention to the usage here, which is to use count() directly;

count() in Countable is the same as the usual count() ) methods

By the way, take a look at the explanation in the PHP source code

You can see that the first parameter can be an array or a countable

Kaka’s understanding is that Countable just rewrites the count method in SPL in order to facilitate customizing the statistical rules you need.

<span style="display: block; background: url(https://my-wechat.mdnice.com/point.png); height: 30px; width: 100%; background-size: 40px; background-repeat: no-repeat; background-color: #282c34; margin-bottom: -7px; border-radius: 5px; background-position: 10px 10px;"></span><code class="hljs" style="overflow-x: auto; padding: 16px; color: #abb2bf; display: -webkit-box; font-family: Operator Mono, Consolas, Monaco, Menlo, monospace; font-size: 12px; -webkit-overflow-scrolling: touch; padding-top: 15px; background: #282c34; border-radius: 5px;">int count ( mixed <span class="hljs-variable" style="color: #d19a66; line-height: 26px;">$array_or_countable</span> [, int <span class="hljs-variable" style="color: #d19a66; line-height: 26px;">$mode</span> = COUNT_NORMAL ] )<br/></code>

The next step is to analyze the containers in the framework and trace them back to the root cause step by step.

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Persistence in learning, persistence in blogging, and persistence in sharing are the beliefs that Kaka has always upheld since his career. I hope that Kaka’s articles in the huge Internet can bring you a little Silk help. My name is Kaka, see you next time.

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