Removing duplicate array, from an array of arrays

This is simple to achieve (and quick since its an internal) with array_unique(). However, by default this function casts everything to a string, so you will need to pass the SORT_REGULAR constant. (Demo)

<?php
$data = array(
    array(
        'id' => 0,
        'title' => 'Abc'
    ),
    array(
        'id' => 2,
        'title' => 'Def',
        'content' => 'Stackoverflow!'
    ),
    array(
        'id' => 0,
        'title' => 'Abc'
    )
);

var_dump(array_unique($data, SORT_REGULAR));

Try this:

<?php

$test=array
(
0 => array
    (
        'id' => '1331',
        'shortname' => 'MCS-115-113C',
        'userid' => '663',
        'email' => '[email protected]',
        'username' => 'FOOBARBAZ',
        'nombrecompleto' => 'asdfasdf',
        'lastlogin' => '1367501486',
    ),
1 => array
    (
        'id' => '1331',
        'shortname' => 'MAFA-EOOF',
        'userid' => '323',
        'email' => '[email protected]',
        'username' => 'FOOBARBAZ',
        'nombrecompleto' => 'asdfasdf',
        'lastlogin' => '136732186'
    ),
2 => array
    (
        'id' => '1331',
        'shortname' => 'MKT-FOOBAR',
        'userid' => '434',
        'email' => '[email protected]',
        'username' => 'adsfasdf',
        'nombrecompleto' => 'asdfasdf',
        'lastlogin' => '1367234486'
    )
);

$userdupe=array();

foreach ($test as $index=>$t) {
    if (isset($userdupe[$t["username"]])) {
        unset($test[$index]);
        continue;
    }
    $userdupe[$t["username"]]=true;
}

print_r($test);
?>