(PHP 5, PHP 7, PHP 8)
Interface for external iterators or objects that can be iterated themselves internally.
PHP already provides a number of iterators for many day to day tasks. See SPL iterators for a list.
Example #1 Basic usage
This example demonstrates in which order methods are called when using foreach with an iterator.
<?phpclass myIterator implements Iterator { private $position = 0; private $array = array( "firstelement", "secondelement", "lastelement", ); public function __construct() { $this->position = 0; } public function rewind(): void { var_dump(__METHOD__); $this->position = 0; } #[\ReturnTypeWillChange] public function current() { var_dump(__METHOD__); return $this->array[$this->position]; } #[\ReturnTypeWillChange] public function key() { var_dump(__METHOD__); return $this->position; } public function next(): void { var_dump(__METHOD__); ++$this->position; } public function valid(): bool { var_dump(__METHOD__); return isset($this->array[$this->position]); }}$it = new myIterator;foreach($it as $key => $value) { var_dump($key, $value); echo "\n";}?>
The above example will output something similar to:
string(18) "myIterator::rewind" string(17) "myIterator::valid" string(19) "myIterator::current" string(15) "myIterator::key" int(0) string(12) "firstelement" string(16) "myIterator::next" string(17) "myIterator::valid" string(19) "myIterator::current" string(15) "myIterator::key" int(1) string(13) "secondelement" string(16) "myIterator::next" string(17) "myIterator::valid" string(19) "myIterator::current" string(15) "myIterator::key" int(2) string(11) "lastelement" string(16) "myIterator::next" string(17) "myIterator::valid"
See also object iteration.