How can I store functions in PHP arrays effectively?

Storing Functions in PHP Arrays

The question arises whether it is possible to store functions within PHP arrays. For instance, consider the following:

$functions = [
  'function1' => function($echo) { echo $echo; }
];

Is this a viable approach? If not, what are the recommended alternatives?

Recommended Approach: Anonymous Functions

The preferred method for storing functions in arrays involves utilizing anonymous functions. Like the example above, they can be defined inline:

$functions = [
  'function1' => fn($echo) => $echo
];

Referencing External Functions

When dealing with pre-declared functions, you can reference them by name as strings:

<code class="php">function do_echo($echo) {
    echo $echo;
}

$functions = [
  'function1' => 'do_echo'
];</code>

Legacy Method (PHP < 5.3): create_function

For older versions of PHP that do not support anonymous functions, the create_function construct can be employed:

<code class="php">$functions = [
  'function1' => create_function('$echo', 'echo $echo;')
];<p><strong>Calling Stored Functions</strong></p>
<p>Regardless of the method used to store the function, it can be invoked directly (PHP >= 5.4) or through call_user_func/call_user_func_array.</p>
<pre class="brush:php;toolbar:false"><code class="php">$functions['function1']('Hello world!');

call_user_func($functions['function1'], 'Hello world!');</code>

In summary, anonymous functions are the recommended approach for storing functions in PHP arrays, with string references being used for pre-declared functions and create_function being available for legacy PHP versions.

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