php man page for iterator

ITERATOR(3)								 1							       ITERATOR(3)

The Iterator interface

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

INTERFACE SYNOPSIS
       Iterator

       Iteratorextends
       Traversable

       Methods

       o abstractpublic mixed Iterator::current (void  )

       o abstractpublic scalar Iterator::key (void  )

       o abstractpublic void Iterator::next (void  )

       o abstractpublic void Iterator::rewind (void  )

       o abstractpublic boolean Iterator::valid (void  )

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.

	      <?php
	      class myIterator implements Iterator {
		  private $position = 0;
		  private $array = array(
		      "firstelement",
		      "secondelement",
		      "lastelement",
		  );

		  public function __construct() {
		      $this->position = 0;
		  }

		  function rewind() {
		      var_dump(__METHOD__);
		      $this->position = 0;
		  }

		  function current() {
		      var_dump(__METHOD__);
		      return $this->array[$this->position];
		  }

		  function key() {
		      var_dump(__METHOD__);
		      return $this->position;
		  }

		  function next() {
		      var_dump(__METHOD__);
		      ++$this->position;
		  }

		  function valid() {
		      var_dump(__METHOD__);
		      return isset($this->array[$this->position]);
		  }
	      }

	      $it = new myIterator;

	      foreach($it as $key => $value) {
		  var_dump($key, $value);
		  echo "
";
	      }
	      ?>

	      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"

PHP Documentation Group 													       ITERATOR(3)