<glacius:metadata>

    <title>array_flatten()</title>

    <description>Implementation of array_flatten() in PHP</description>

    <category>Legacy blog posts</category>

    <category>Programming</category>

    <category>PHP</category>

</glacius:metadata>

<glacius:macro name="legacy blargh banner">

    <properties>

        <originalUrl>https://tmont.com/blargh/2009/6/array_flatten</originalUrl>

        <originalDate>2009-06-19T07:33:51.000Z</originalDate>

    </properties>

</glacius:macro>

<p>How exactly is this function not in the PHP core yet?</p>

<glacius:code lang="php"><![CDATA[

function array_flatten($arr) {

	$flattened = array();

	if (is_array($arr)) {

		foreach ($arr as $value) {

			$flattened = array_merge($flattened, array_flatten($value));

		}

	} else {

		$flattened[] = $arr;

	}

	return $flattened;

}

]]></glacius:code>

<p>Usage:</p>

<glacius:code lang="php"><![CDATA[

$a = array(

	'foo' => 'bar',

	'baz' => array(1, 2, 3, 4, 5),

	'bat' => array(

		'a', 

		array(

			'b', 

			array(

				'c', 

				array('d')

			)

		)

	)

);

print_r(array_flatten($a));

/*

Array

(

    [0] => bar

    [1] => 1

    [2] => 2

    [3] => 3

    [4] => 4

    [5] => 5

    [6] => a

    [7] => b

    [8] => c

    [9] => d

)

*/

]]></glacius:code>

<p>

  <a href="https://www.php.net/manual/en/function.array-values.php#86784">This version</a> is 

  interesting, but using <code>create_function()</code> is rarely a good idea, since it's

  never garbage collected.

</p>