Codeigniter dynamic multiple instances for loading custom library - codeigniter

Question

I wanted to create instances in a loop, which means the number of instances totally depends on the loop. I'm not able to achieve it.
I've come across many posts regarding the same and was successful for,
$this->load->library('stlstats', $param, 'instance1');
$volume1 = $this->instance1->getVolume($unit);
$this->load->library('stlstats', $param, 'instance2');
$volume2 = $this->instance2->getVolume($unit);
//Don't bother about $param and $unit, those are pre-defined.
So, in the above code, I'm able to achieve getting different volumes. But I want it to be created each iteration. If I place the code inside the loop say,
$this->load->library('stlstats', $param, 'instance1');
$volume1 = $this->instance1->getVolume($unit);
And print $volume1, then the output is the same for all the iteration.
Since I have no idea about the number of iterations of the loop, how can I achieve this?
Thank you all :)

Answer 1

You placed this code in a loop:
$this->load->library('stlstats', $param, 'instance1');
$volume1 = $this->instance1->getVolume($unit);
But where is the loop variable?
You are always using the same instance alias 'instance1'.
A simple solution will be for example (COUNT is the number of iterations):
$volume = array(); // Store all volumes in array
for ($i = 1; $i < COUNT; $i++) {
$instance = 'instance' . $i;
$this->load->library('stlstats', $param, $instance);
$volume[$i] = $this->$instance->getVolume($unit); // Add value to array
}

Answer 2

CodeIgniter caches the already loaded libraries, so it will give back the same instance.
By the way you shouldn't create multiple instances, instead you should re-organize your library code (instead of set the params in the constructor you should create a setter method) like this:
// library
class Stlstats {
protected $params = array();
public function __construct() {
}
public function setParam($params) {
$this->params = $params;
}
public function getVolume($unit) {
$this->params = $params;
// example code:
return ($unit * $params['distance']);
}
}
// load once the library
$this->load->library('stlstats');
// test data
$unit = 22;
$all_params = array(
array('distance'=>3),
array('distance'=>5),
array('distance'=>7),
);
// use it in loop
foreach($all_params as $params) {
$this->stlstats->setParam($param);
echo $this->stlstats->getVolume($unit);
}

Answer 3

The answer is very simple. I'm sure many might have come across this situation and I hope this answers.
$this->load->library('stlstats', $param, 'instance1');
$volume1 = $this->instance1->getVolume($unit);
Place the above code into the loop and at the end of the loop include this,
unset($this->instance1);
As simple as that :)
Thank you #Zaragoli your answer made me think in a right way :) Cheers!!