Optional argument in Drupal hook_menu implementation

How can I set one of the page arguments in my drupal menu item as an optional page argument?

I have

$items['activities_list/%/%']=array(
'title callback' => 'activities_list_title',
'title arguments' =>array(1),
'description' =>'All the Indicators divided by Coutry',
'page callback' => 'activities_list',
'access arguments' => array('access ppi'),
'page arguments' => array(1,2)
);

If I call activities_list/76 for example without a third argument I will receive a page not found error. How Can I set the Third parameter as an optional one?

Thanks!

I don't think you can. If you did this instead with only one wildcard:

$items['activities_list/%']=array(
'title callback' => 'activities_list_title',
'title arguments' =>array(1),
'description' =>'All the Indicators divided by Coutry',
'page callback' => 'activities_list',
'access arguments' => array('access ppi'),
'page arguments' => array(1,2)
);

This will then work for a URL like **activities_list/foo**, but if you then had a URL like **activities_list/foo/bar** you can still get the value of **bar** in the page callback as it is still passed to that function by **'page arguments' => array(1,2)**.

Or alternatively you can call it by using **arg(2)** in your page callback.

It's easier than you think :). Don't set any arguments in your path and just pass them to your "page callback" function.

$items['activities_list']=array(
'title callback' => 'activities_list_title',
'description' =>'All the Indicators divided by Coutry',
'page callback' => 'activities_list',
'access arguments' => array('access ppi'),
);

And the page callback function would look like this:

function activities_list($arg1, $arg2)
{
// Your code goes here...
drupal_set_title(activities_list_title($arg1, $arg2));
}

You can alter the page title using the following code. (Not tested, kindly let me know if it worked):

function activities_list_title($arg_1, $arg_2)
{
$title = "";
// Your code goes here
return $title;
}

Hope this helps... Muhammad.