in_array

(PHP 4 >= 4.0.0)

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

Description

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() function 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.

Note: In PHP versions before 4.2.0 needle was not allowed to be an array.

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

<?php
$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

Example 3. in_array() with an array as needle

<?php
$a = array(array('p', 'h'), array('p', 'r'), 'o');

if (in_array(array ('p', 'h'), $a))
    echo "'ph' is found\n";
if (in_array(array ('f', 'i'), $a))
    echo "'fi' is not found\n";
if (in_array('o', $a))
    echo "'o' is found\n";
?>

// This will output:

'ph' is found
'o' is found

See also array_search().