form_button([$data = ''[, $content = ''[, $extra = '']]])

class CI_Cart $product_id_rules = '.a-z0-9_-' These are the regular expression

platform()

class CI_Unit_test set_test_items($items)

nl2br_except_pre($str)

limit_characters($str[, $n = 500[, $end_char = '…']])

or_group_start()

class CI_Session userdata([$key = NULL])

$this->db->call_function(); This function enables you to call PHP database functions that are not natively included in CodeIgniter,

array_column(array $array, $column_key[, $index_key = NULL])