Online PHP editor | refs for F9nQa

<?php $fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple"); function test_alter(&$item1, $key, $prefix) { $item1 = "$prefix: $item1"; } function test_print($item2, $key) { echo "$key. $item2<br />\n"; } echo "Before ...:\n"; array_walk($fruits, 'test_print'); // array_walk($fruits, 'test_alter', 'fruit'); echo "... and after:\n"; array_walk($fruits,function($value, $key){$key = $value; $value=false;}); var_dump($fruits);