Arrays -- How do I insert a pair of data into an array

I am attempting to insert a set of data (actually a pair) into an array, without much success. I would like to insert the data set ("course number", "course title") into a numerically indexed array so that when I want to output the array I can reference it like so: echo("$array[$i]["course_num"] $array[$i]["course_title"]"); // where $i is just the index value that increments I tried building the array like so (where $tuple[....] is a valid result set from pg_fetch_row(): $array[] = array("course_num" => $tuple[crn], "course_title" => $tuple[course_name]); But all I gets outputted is: Array["course_num"] Array["course_title"] Any help with this would be greatly appreciated. Thanks.