Instead of doing foreach() loop on the array, it would be faster to use array_search() to find the proper key. On small arrays, I would go with foreach for better readibility, but for bigger arrays, or often executed code, this should be a bit more optimal:
$result=array_search($unwantedValue,$array,true);
if($result !== false) {
unset($array[$result]);
}
The strict comparsion operator !== is needed, because array_search() can return 0 as the index of the $unwantedValue.
Also, the above example will remove just the first value $unwantedValue, if the $unwantedValue can occur more then once in the $array, You should use array_keys(), to find all of them:
$result=array_keys($array,$unwantedValue,true)
foreach($result as $key) {
unset($array[$key]);
}
Check http://php.net/manual/en/function.array-search.php for more information.