Recursively calculate totals from an array of arrays (with matching keys, etc)

recursive-array-calculate.php

<?php
/**
 * Calculate totals from a nested array. Handles nested recursion.
 * Uses first nested array as the "pattern" for building the totals array.
 *
 * @param  array  $to_count The multi-dimensional array to calculate the totals for.
 *
 * @return array            The array of totals.
 */
function calculate_array_totals( $to_count ) {
	return _calculate_array_totals( $to_count[ key( $to_count ) ], $to_count );
}

/**
 * Calculate totals from a nested array. Handles nested recursion.
 * Uses first parameter as the "pattern" for building the totals array.
 *
 * @param  array  $totals   The pattern of the totals. Should match the keys you
 *                          want to calculate the totals for.
 * @param  array  $to_count The multi-dimensional array to calculate the totals for.
 *
 * @return array            The $totals array with calculated totals.
 */
function _calculate_array_totals( $totals, $to_count ) {
	foreach ( $totals as $key => $value ) {
		if ( is_array( $value ) ) {
			// Handle recursion.
			$_counts = array();
			foreach ( $to_count as $parent_key => $array_counts ) {
				if ( isset( $array_counts[ $key ] ) ) {
					$_counts[] = $array_counts[ $key ];
				}
			}
			$totals[ $key ] = _calculate_array_totals( $value, $_counts );
		} else {
			$value = 0;
			foreach ( $to_count as $parent_key => $array_counts ) {
				if ( isset( $array_counts[ $key ] ) && is_numeric( $array_counts[ $key ] ) ) {
					$value += $array_counts[ $key ];
				}
			}

			// If we stumbled on a non-numeric value, remove this.
			if ( ! $value && ! is_numeric( $totals[ $key ] ) ) {
				unset( $totals[ $key ] );
			} else {
				$totals[ $key ] = $value;
			}
		}
	}

	return $totals;
}

$to_count = array(
	array(
		'Facebook' => array(
			'do_share' => true, // Will be ignored/discarded from totals.
			'share_count' => 34,
			'like_count' => 0,
			'comment_count' => 10,
			'total_count' => 64,
			'extra-nested' => array(
				'share_count' => 999,
				'like_count' => 1,
				'comment_count' => 10,
				'total_count' => 64,
			),
		),
		'Twitter' => 12,
		'Pinterest' => 177,
		'LinkedIn' => 0,
		'GooglePlusOne' => 0,
		'StumbleUpon' => 0,
	),
	array(
		'Facebook' => array(
			'do_share' => false, // Will be ignored/discarded from totals.
			'share_count' => 116,
			'like_count' => 0,
			'comment_count' => 54,
			'total_count' => 296,
			'extra-nested' => array(
				'share_count' => 116,
				'like_count' => 0,
				'comment_count' => 54,
				'total_count' => 296,
			),
		),
		'Twitter' => 0,
		'Pinterest' => 1878,
		'LinkedIn' => 0,
		'GooglePlusOne' => 0,
		'StumbleUpon' => 0,
	),
	array(
		'Facebook' => array(
			'do_share' => null, // Will be ignored/discarded from totals.
			'share_count' => 1,
			'like_count' => 2,
			'comment_count' => 3,
			'total_count' => 4,
			'extra-nested' => array(
				'share_count' => 116,
				'like_count' => 0,
				'comment_count' => 54,
				'total_count' => 296,
			),
		),
		'Twitter' => 0,
		'Pinterest' => 1,
		'LinkedIn' => 2,
		'GooglePlusOne' => 3,
		'StumbleUpon' => 4,
	),
);

// $totals = calculate_array_totals( $to_count );
/*
Generates: Array
(
    [Facebook] => Array
        (
            [share_count] => 151
            [like_count] => 2
            [comment_count] => 67
            [total_count] => 364
            [extra-nested] => Array
                (
                    [share_count] => 1231
                    [like_count] => 1
                    [comment_count] => 118
                    [total_count] => 656
                )

        )

    [Twitter] => 12
    [Pinterest] => 2056
    [LinkedIn] => 2
    [GooglePlusOne] => 3
    [StumbleUpon] => 4
)
*/