This is the correct use of array push
$array = array("10","20","30","40");
$new_val = "50";
array_push($array,$new_val);
then when you do print_r($array) you'll get
[0]=>10
[1]=>20
[2]=>30
[3]=>40
[4]=>50
you only pass the value, don't try and pass the key as its automatically be assigned
Gary Mailer