How to unset (remove) a collection element after fetching it?

I have a collection which I want to iterate and modify while I fetch some of its elements. But I could't find a way or method to remove that fetched element.

$selected = []; 
foreach ($collection as $key => $value) {
      if ($collection->selected == true) {
          $selected[] = $value;
          unset($value);
      }
}

This is just a representation of my question for demonstration.

After @Ohgodwhy advice the forget() function I checked it again and saw that I actually misunderstood the function. It was exactly as I was looking for.

So for working solution I have added $collection->forget($key) inside the if statement.

Below is the working solution of my problem, using @Ohgodwhy's solution:

$selected = []; 
foreach ($collection as $key => $value) {
      if ($collection->selected == true) {
          $selected[] = $value;
          $collection->forget($key);
      }
}

(this is just a demonstration)

Solution 1:

You would want to use ->forget()

$collection->forget($key);

Link to the forget method documentation

Solution 2:

Or you can use reject method

$newColection = $collection->reject(function($element) {
    return $item->selected != true;
});

or pull method

$selected = []; 
foreach ($collection as $key => $item) {
      if ($item->selected == true) {
          $selected[] = $collection->pull($key);
      }
}