The "in_array" function can search for array elements if a given value exists

    in_array(search,array,type)

In the above syntax "array" is the array in which the elements value specified in "search" has to be looked for. The "type" is an optional field which specifies the type of the search value.

    <?php
    $s = array("Mac", "NT", "Irix", "Linux");
    if (in_array("Irix", $s)) 
      {
        echo "Got Irix";
      }
    if (in_array("mac", $s)) 
      {
        echo "Got mac";
      }
    ?>

    Got Irix

In the above example since the in_array() is case sensitive, displays the result from the first "if" condition.