How can you access class constants dynamically in PHP?

Accessing Class Constants Dynamically

In PHP, accessing class constants dynamically using a variable variable can be challenging. However, there are two effective methods to accomplish this:

Using the Constant Function

The constant() function accepts a string argument representing the constant name and evaluates it:

<br>self:: <br>{</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">const MY_CONST = 'myval';

static function test()
{
    $c = 'MY_CONST';
    return constant('self::'. $c);
}

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}

echo A::test(); // output: myval

In this example, the constant() function evaluates the string "self::MY_CONST" and returns the value of the MY_CONST constant.

Using Reflection

Reflection allows you to access information about classes, methods, and constants dynamically:

<br>$ref = new ReflectionClass('A');<br>$constName = 'MY_CONST';<br>echo $ref->getConstant($constName); // output: myval<br>

Here, the ReflectionClass object is created for the A class. The getConstant() method then returns the value of the MY_CONST constant.

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