Wordpress - Change page dynamically but within shortcode running php - wordpress

Question

I am using a custom shortcode plugin. The plugin allows me to run some php. The php queries a non-wp database to build a page of vehicle specs and everything works great. The issue is that all of the information needed for the page title and description is contained within the data coming from the database. I've tried some of the standard wp php filters but the title does not change.
Is this not possibly because of the execution timing of the shortcode?
TinyMCE in WP admin. Shortcode
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[myplugin data_id='42']
PHP window in shortcode editor
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$GP=array_merge($_GET, $_POST);
echo "hello word" //works
echo $data_id; //works
echo $GP[some_post_data]; //works
//connect to database (irrelevant)
echo "the title from data table for data_id 42 = ".$data[title]; //works
// the following has no effect on page title even though $data[title] contains valid data
add_filter('the_title','myCallback');
function myCallback($data){
return $data[title];
}

Answer 1

The problem is that $data[title] is out of scope, and that your filter callback is set up incorrectly. Also, you SHOULD encapsulate associative indexes with quotes.
When adding a callback to an existing filter, the arguments within the callback are passed by the filter definition. Case and point: Filtering The Title
The arguments within a standard filter for the_title are $title and $id. If you want to return the title from your $data array, you can do it the sloppy way using the global scope:
add_filter('the_title','myCallback');
function myCallback($title, $id){
global $data;
return $data['title'];
}
But personally, I would look into avoiding globals altogether and concentrate on utilizing custom filters. Look into Adding Your Own Hooks. After getting a handle on action hooks, Filter Hooks are pretty easy to grasp.