- in_array: documentation ( source)
<?php
foreach(array('100', '1000', '2000', '3000') as $_GET['id']){
if(!isset($_GET['id']) || !in_array($_GET['id'], array('1000', '2000'))){
echo 'not 1k or 2 k' . $_GET['id'] . PHP_EOL;
} else {
echo 'is 1k or 2k' . $_GET['id'] . PHP_EOL;
}
}