PHP: Merge/Add multi-dimensional array?

arrays, merge, php

Solution

It's not possible with standard means of PHP, you should write your own function:

Code

function readArray( $arr, $k, $default = 0 ) {
    return isset( $arr[$k] ) ? $arr[$k] : $default ;
}

function merge( $arr1, $arr2 ) {
    $result = array() ;
    foreach( $arr1 as $k => $v ) {
        if( is_numeric( $v ) ) {
            $result[$k] = (int)$v + (int) readArray( $arr2, $k ) ;
        } else {
            $result[$k] = merge( $v, readArray($arr2, $k, array()) ) ;
        }
    }
    return $result ;
}

Test

$basketA = array( "fruit" => array(), "drink" => array() ) ;
$basketA['fruit']['apple'] = 1;
$basketA['fruit']['orange'] = 2;
$basketA['fruit']['banana'] = 3;
$basketA['drink']['soda'] = 4;
$basketA['drink']['milk'] = 5;

$basketB = array( "fruit" => array(), "drink" => array() ) ;
$basketB['fruit']['apple'] = 2;
$basketB['fruit']['orange'] = 2;
$basketB['fruit']['banana'] = 2;
$basketB['drink']['soda'] = 2;
$basketB['drink']['milk'] = 2;

$basketC = merge( $basketA, $basketB ) ;
print_r( $basketC ) ;

Output

Array
(
    [fruit] => Array
        (
            [apple] => 3
            [orange] => 4
            [banana] => 5
        )

    [drink] => Array
        (
            [soda] => 6
            [milk] => 7
        )

)

Problem

Original source