Php/docs/class.iterator

• PHP Manual
• Predefined Interfaces and Classes
• The Iterator interface

(PHP 5, PHP 7, PHP 8)

Introduction

Interface for external iterators or objects that can be iterated themselves internally.

Interface synopsis

Iterator extends Traversable {

/* Methods */

abstract public current ( ) : mixed

abstract public key ( ) : scalar

abstract public next ( ) : void

abstract public rewind ( ) : void

abstract public valid ( ) : bool

}

Predefined iterators

PHP already provides a number of iterators for many day to day tasks. See SPL iterators for a list.

Examples

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() {        var_dump(__METHOD__);        $this->position = 0;    }    public function current() {        var_dump(__METHOD__);        return $this->array[$this->position];    }    public function key() {        var_dump(__METHOD__);        return $this->position;    }    public function next() {        var_dump(__METHOD__);        ++$this->position;    }    public function valid() {        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"

Table of Contents

• Iterator::current — Return the current element
• Iterator::key — Return the key of the current element
• Iterator::next — Move forward to next element
• Iterator::rewind — Rewind the Iterator to the first element
• Iterator::valid — Checks if current position is valid