$colors = array("blue","green","red");
//delete element in array by value "green"
if (($key = array_search("green", $colors)) !== false) {
unset($colors[$key]);
}
<?php
$array = array('a','b','c','d','e');
unset($array[4]);
print_r($array);
?>
Array
(
[0] => a
[1] => b
[2] => c
[3] => d
)
unset($dataArray['key']);
unset($array['key-here']);