Online PHP editor | output for KElB5

@ 2018-08-17T20:38:10Z

<?php
$array = [
    1 => ['quantity' => 2, 'product_id' => 1, 'option_id' => 22],
    2 => ['quantity' => 2, 'product_id' => 2, 'option_id' => 22],
    3 => ['quantity' => 3, 'product_id' => 2, 'option_id' => 22],
    4 => ['quantity' => 1, 'product_id' => 2, 'option_id' => 25]
];

$result = [null];  // create placeholding element
foreach($array as $subarray){
    $composite_key = $subarray['product_id'] . '_' . $subarray['option_id'];
    if(!isset($result[$composite_key])){
        $result[$composite_key] = $subarray;  // first occurrence
    }else{
        $result[$composite_key]['quantity'] += $subarray['quantity'];  // not first occurrence
    }
}
$result=array_values($result);  // change from assoc to indexed
unset($result[0]);  // remove first element to start numeric keys at 1
var_export($result);

Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.4, 8.3.6: array ( 1 => array ( 'quantity' => 2, 'product_id' => 1, 'option_id' => 22, ), 2 => array ( 'quantity' => 5, 'product_id' => 2, 'option_id' => 22, ), 3 => array ( 'quantity' => 1, 'product_id' => 2, 'option_id' => 25, ), )
Output for 8.3.5: Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0 array ( 1 => array ( 'quantity' => 2, 'product_id' => 1, 'option_id' => 22, ), 2 => array ( 'quantity' => 5, 'product_id' => 2, 'option_id' => 22, ), 3 => array ( 'quantity' => 1, 'product_id' => 2, 'option_id' => 25, ), )

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