W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<body>

<?php
// Create an Iterator
class MyIterator implements Iterator {
  private $items = [];
  private $pointer = 0;

public function __construct($items) {
    // array_values() makes sure that the keys are numbers
    $this->items = array_values($items);
  }

public function current() {
    return $this->items[$this->pointer];
  }

public function key() {
    return $this->pointer;
  }

public function next() {
    $this->pointer++;
  }

public function rewind() {
    $this->pointer = 0;
  }

public function valid() {
    // count() indicates how many items are in the list
    return $this->pointer < count($this->items);
  }
}

// A function that uses iterables
function printIterable(iterable $myIterable) {
  foreach($myIterable as $item) {
    echo $item;
  }
}

// Use the iterator as an iterable
$iterator = new MyIterator(["a", "b", "c"]);
printIterable($iterator);
?>

</body>

</html>