Codeigniter: Variables/Config Items within Language Files

In CI Forum, nlogachev suggest better solution.
It can switch variables order.

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');class MY_Language extends CI_Language{    function MY_Language()    {        parent::CI_Language();    }    /**     * Fetch a single line of text from the language array. Takes variable number     * of arguments and supports wildcards in the form of '%1', '%2', etc.     * Overloaded function.     *     * @access public     * @return mixed false if not found or the language string     */    public function line()    {        //get the arguments passed to the function        $args = func_get_args();        //count the number of arguments        $c = count($args);        //if one or more arguments, perform the necessary processing        if ($c)        {            //first argument should be the actual language line key            //so remove it from the array (pop from front)            $line = array_shift($args);            //check to make sure the key is valid and load the line            $line = ($line == '' OR ! isset($this->language[$line])) ? FALSE : $this->language[$line];            //if the line exists and more function arguments remain            //perform wildcard replacements            if ($line && $args)            {                $i = 1;                foreach ($args as $arg)                {                    $line = preg_replace('/\%'.$i.'/', $arg, $line);                    $i++;                }            }        }        else        {            //if no arguments given, no language line available            $line = false;        }        return $line;    }}?> 

use case~

//in english$lang['some_key'] = 'Some string with %1 %2.';//in another language$lang['some_key'] = 'Some string %2 with %1.';//the actual usageecho $this->lang->line('some_key','first','second'); 

Your best bet is probably to put a placeholder in there, then swap it out in your controller.

Lang file:

<?php $lang['error_activation_key_expired'] = 'The activation key you have attempted using has expired. Please request a new Activation Key <a href="%s/member/request_activation" title="Request a New Activation Key">here</a>.';

In controller:

$activation_message = sprintf($this->lang->line('error_activation_key_expired'), $base_url);