Extract items from an array (or collection for Laravel) using a callback function for comparison

array-extract.php

<?php

if(!function_exists('arrayExtract')){
    /**
     * Extract items from an array and return them using a callback function to
     * compare values
     *
     * @param array     $arr
     * @param Callable  $callback
     * @param bool      $preserve
     *
     * @return array
     */
    function arrayExtract(array &$arr, Callable $callback, $preserve = false){
        $filtered = array_filter($arr, $callback);

        if(count($filtered)){
            $arr = array_diff_key($arr, $filtered);

            if(!$preserve){
                $arr = array_values($arr);
            }
        }

        return $filtered;
    }
}

collection-extract.php

<?php

// Note: This is Laravel collection specific

if(!function_exists('collectionExtract')){
    /**
     * Extract items from a collection and return them using a callback function to
     * compare values
     *
     * @param \Illuminate\Support\Collection    $collection
     * @param Callable                          $callback
     * @param bool                              $preserve
     *
     * @return \Illuminate\Support\Collection
     */
    function collectionExtract(
        \Illuminate\Support\Collection &$collection,
        Callable $callback,
        $preserve = false
    ){
        $filtered = $collection->filter($callback);

        if(count($filtered)){
            $collection = $collection->diffKeys($filtered);

            if(!$preserve){
                $collection = $collection->values();
            }
        }

        return $filtered;
    }
}

examples.php

<?php

// Arrays

$arr1 = [0, 1, 2, 3, 4, 5];
$arr2 = arrayExtract($arr1, function($value){
    return $value > 2 && $value < 4;
});

/**
 * Returns this
 *   array:5 [
 *     0 => 0
 *     1 => 1
 *     2 => 2
 *     3 => 4
 *     4 => 5
 *   ]
 *   array:1 [
 *     3 => 3
 *   ]
 */

$arr3 = ['first' => 0, 'second' => 1, 'third' => 2, 'fourth' => 3, 'fifth' => 4, 'sixth' => 5];
$arr4 = arrayExtract($arr3, function($value){
    return $value > 2 && $value < 4;
}, true);

/**
 * Returns this
 *   array:5 [
 *     "first" => 0
 *     "second" => 1
 *     "third" => 2
 *     "fifth" => 4
 *     "sixth" => 5
 *   ]
 *   array:1 [
 *     "fourth" => 3
 *   ]
 */

// Collections

$collection1 = collect([0, 1, 2, 3, 4, 5]);
$collection2 = collectionExtract($collection1, function($value){
    return $value > 2 && $value < 4;
});

/**
 * Returns this
 *   Collection {#476
 *     #items: array:5 [
 *       0 => 0
 *       1 => 1
 *       2 => 2
 *       3 => 4
 *       4 => 5
 *     ]
 *   }
 *   Collection {#477
 *     #items: array:1 [
 *       3 => 3
 *     ]
 *   }
 */

$collection3 = collect(['first' => 0, 'second' => 1, 'third' => 2, 'fourth' => 3, 'fifth' => 4, 'sixth' => 5]);
$collection4 = collectionExtract($collection3, function($value){
    return $value > 2 && $value < 4;
}, true);

/**
 * Returns this
 *   Collection {#476
 *     #items: array:5 [
 *       "first" => 0
 *       "second" => 1
 *       "third" => 2
 *       "fifth" => 4
 *       "sixth" => 5
 *     ]
 *   }
 *   Collection {#477
 *     #items: array:1 [
 *       "fourth" => 3
 *     ]
 *   }
 */