array_map tutorial

array_map.php

<?php
/**
 * Template Name: array_map()
 *
 * @package WordPress
 * @subpackage Twenty_fifteen
 */

/**
 *
 * A very simple example of how array_map works
 *
 */
$array_map = array( 10, 20, 30 );

function multiple_array_values($n) {

	return $n * 2;

}

$new_array = array_map( 'multiple_array_values', $array_map );

var_dump($new_array);

/**
 *
 * Behind the scenes this is what array_map is doing.
 * Looping through an array and executing some sort of function.
 */

function another_example($array_map) {

	$foreach_example = array();

	foreach( $array_map as $value ) {

		$foreach_example[] = $value * 2;

	}

	return $foreach_example;
}

var_dump(another_example($array_map));

/**
 *
 * In WordPress post Meta is a great use-case for array_map.
 * Here I simply show you what get_post_meta will normally return.
 * As well as, how to access the values.
 *
 */

//$post_meta = get_post_meta( get_the_ID() );

$post_meta = array(
	'first_name' => array(
		'Bobby'
	),
	'channel' => array(
		'Develop with WP'
	),
	'num_vids' => array(
		32
	),
	'num_views' => array(
		9000
	),
	'num_likes' => array(
		22
	)
);

var_dump( $post_meta['first_name'][0] );

/**
 *
 * But by using array_map we can make using post meta cleaner, and easier to do.
 *
 */

function clean_post_meta( $a ) {

	return $a[0];

}

$cleaned_post_meta = array_map( 'clean_post_meta', $post_meta );

var_dump( $cleaned_post_meta );
var_dump( $cleaned_post_meta['first_name']);