in_array() and multidimensional array

in_array() does not work on multidimensional arrays. You could write a recursive function to do that for you:

function in_array_r($needle, $haystack, $strict = false) {    foreach ($haystack as $item) {        if (($strict ? $item === $needle : $item == $needle) || (is_array($item) && in_array_r($needle, $item, $strict))) {            return true;        }    }    return false;}

Usage:

$b = array(array("Mac", "NT"), array("Irix", "Linux"));echo in_array_r("Irix", $b) ? 'found' : 'not found';

If you know which column to search against, you can use array_search() and array_column():

$userdb = Array(    (0) => Array        (            ('uid') => '100',            ('name') => 'Sandra Shush',            ('url') => 'urlof100'        ),    (1) => Array        (            ('uid') => '5465',            ('name') => 'Stefanie Mcmohn',            ('url') => 'urlof5465'        ),    (2) => Array        (            ('uid') => '40489',            ('name') => 'Michael',            ('url') => 'urlof40489'        ));if(array_search('urlof5465', array_column($userdb, 'url')) !== false) {    echo 'value is in multidim array';}else {    echo 'value is not in multidim array';}

This idea is in the comments section for array_search() on the PHP manual;

This will work too.

function in_array_r($item , $array){    return preg_match('/"'.preg_quote($item, '/').'"/i' , json_encode($array));}

Usage:

if(in_array_r($item , $array)){    // found!}