Best way to implement dynamic site-wide menu?

Thanks ...

... So, taking your idea, I could create a Mycontroller, create the html in the construct function (thereby only running it once) and then rather than using the code I have in my controllers now:

PHP Code:

$this->data['title'] = '';
 $this->data['images'] = $images; 
 $this->data['data'] = $output;
 $this->data['view'] = 'v_home';
 $this->load->view('v_template', $this->data); 


Simply have a simple render function like this in My_Controller:

PHP Code:

function _render($data = []) {
    $data['nav']=$this->html; // $this->html created in construct function
    $this->load->view('v_template, $data);
  } 


and call it from my controller like:

PHP Code:

$this->data['title'] = '';
 $this->data['images'] = $images; 
 $this->data['data'] = $output;
 $this->data['view'] = 'v_home';
_render($this->data) 


As I said I'm VERY rusty with this stuff so thanks for any help!!