sytax to remove specifc item in string-indexed array???

Hi everyone: I would like to know how to specific item in array. For the add new item to array, we know just : $array += array("$key" => "$value"); How to remove specific item in array??? I tried --> $array -= ("$key" => "$value"); Don't work... >_<..... Before, i saw some code in other website, they used... $array[$index] -= $value <-- to remove??????? ### i think this just work to number-indexed array.... not for string-indexed array Thank for you help Vincent Ma