- in_array: documentation ( source)
- array_keys: documentation ( source)
<?php
$array = array(0 => 200, '730404' => 89730 ,'730205' => 1000 ,'730100' => 1000 ,'730601' => 2184);
$keys = array_keys($array);
$key='730404';
if (in_array($key,$keys)) {
echo "si es";
}
//print_r($keys);
?>