PHP IteratorAggregate interface

Introduction

IteratorAggregate interface extends abstract Traversable interface. It is implemented by a class to create external iterator. This interface introduces on abstract method called getIterator.

Syntax

IteratorAggregate extends Traversable {
   /* Methods */
   abstract public getIterator ( void ) : Traversable
}

Methods

IteratorAggregate::getIterator — Retrieve an external iterator

This function has no parameters and returns an instance of an object implementing Iterator or Traversable.

IteratorAggregate Example

In following PHP script, a class that implements IteratorAggregate interface contains an array as a propertyThe getIterator() method returns ArrayIterator object out of this array. We can traverse the array using foreach loop.

Example

<?php
class myIterator implements IteratorAggregate {
   public $arr;
   public function __construct() {
      $this->arr = array(10,20,30,40);
   }
   public function getIterator() {
      return new ArrayIterator($this->arr);
   }
}
$obj = new myIterator();
foreach($obj as $key => $value) {
   echo $key ." =>" . $value . "\n";
}
?>

Output

traversal of array property shows following result

0=>10
1=>20
2=>30
3=>40