(PHP 4 >= 4.0.0)

in_array -- Return TRUE if a value exists in an array


bool in_array (mixed needle, array haystack [, bool strict])

Searches haystack for needle and returns TRUE if it is found in the array, FALSE otherwise.

If the third parameter strict is set to TRUE then the in_array() will also check the types of the needle in the haystack.

Note: If needle is a string, the comparison is done in a case-sensitive manner.

Example 1. in_array() example

$os = array ("Mac", "NT", "Irix", "Linux");
if (in_array ("Irix", $os)) {
    print "Got Irix";
if (in_array ("mac", $os)) {
    print "Got mac";

The second condition fails because in_array()() is case-sensitive, so the program above will display:
Got Irix

Example 2. in_array() with strict example

$a = array('1.10', 12.4, 1.13);

if (in_array('12.4', $a, TRUE))
    echo "'12.4' found with strict check\n";
if (in_array(1.13, $a, TRUE))
    echo "1.13 found with strict check\n";

This will display:
1.13 found with strict check

See also array_search().