Codeigniter 2.1，PHP - 从键值对中获取随机数组

Question

I have query from which I need to take random values (random rows) and limit to, lets say, 5 results and subtract them from main array (query). How can I do this?

This is query function:

public function galerija_jedna_slike()
    {
        $galerija = $this->db->order_by('id_galerija', 'RANDOM')->limit(1)->get($this->table)->row();
        $q = " SELECT * FROM galerija_slike
                LEFT JOIN galerije
                ON galerija_slike.galerija_id = galerije.id_galerija
                WHERE galerija_id = $galerija->id_galerija ";
        return $this->db->query($q)->result_array();
    }

I managed to get random values, and now I need to remove those values from the main array. Function:

function array_random_assoc($arr, $num = 1) {
        $keys = array_keys($arr);
        shuffle($keys);

        $r = array();
        for ($i = 0; $i < $num; $i++) {
        $r[$keys[$i]] = $arr[$keys[$i]];
        }
        return $r;
    }

Answer 1

Load the entire table:

$gallery =  $this->db->query("SELECT * FROM gallery;");

Let choose five random rows from gallery:

$max_items = 5;
$num = $query->num_rows();
$row = $query->row(rand(0, $num - 1));
$minus = array(); //store the ids to include

for ($i = 0; $i < $max_items; $i ++)
    $minus[] = $gallery ->row(rand(0, $num - 1));

Iterate the gallery to build two arrays, 1. Gallery minus random rows 2. Random rows

$data = array();
foreach ($gallery ->result() as $row)
{
    if (in_array($row->id, $minus))
        $data['random'][] = $row
    else
        $data['gallery'][] = $row
}

Now, the array $data['gallery'] has all the items without the randon rows. And $data[random] is an array containing the random rows.