Wacław Jacek

Today I was working on some code that had arrays structured like this:

$foo = [
	'a' => [ 1, 2, 3, 4 ],
	'b' => [ 5, 6, 7 ],
];

I needed to calculate the total number of items in the nested arrays. I didn’t find a PHP function to help me with that but I came up with this idea:

$total_count = array_sum( array_map( 'count', $foo ) ); // This returns 7.

How this works

The array_map( 'count', $foo ) part replaces the subarrays in $foo with the result of calling count() on them:

$subarray_counts = array_map( 'count', $foo );

/*
 * Result of print_r( $subarray_counts ):
 *
 *    Array
 *    (
 *        [a] => 4
 *        [b] => 3
 *    )
 */

The array_sum() function then calculates the sum of the values in the resulting array (each being a number of items contained in a given subarray):

$total_count = array_sum( $subarray_counts );

/*
 * Result of print_r( $total_count ): 7
 */

Please let me know if you found this idea useful! 🙂