I use in_array() to check whether a value exists in an array like below,
in_array()
$a = array(\"Mac\", \"NT\", \"Irix\", \"Linux\"); if (in_array(\"Irix\"
I believe you can just use array_key_exists nowadays:
"NT","Irix"=>"Linux"); if (array_key_exists("Mac",$a)) { echo "Key exists!"; } else { echo "Key does not exist!"; } ?>