array key value foreach in php code example

Example 1: for each php

<?php
$arr = array(1, 2, 3, 4);
foreach ($arr as &$value) {
    $value = $value * 2;
}
// $arr is now array(2, 4, 6, 8)
unset($value); // break the reference with the last element
?>

Example 2: for each php

foreach (array_expression as $value)
    statement
foreach (array_expression as $key => $value)
    statement