# The SeekableIterator interface

(PHP 5 >= 5.1.0, PHP 7)

## Introduction

The Seekable iterator.

## Interface synopsis

SeekableIterator extends Iterator {
/* Methods */
abstract public seek ( int `$position` ) : void
/* Inherited methods */
abstract public Iterator::current ( ) : mixed
abstract public Iterator::key ( ) : scalar
abstract public Iterator::next ( ) : void
abstract public Iterator::rewind ( ) : void
abstract public Iterator::valid ( ) : bool
}

Example #1 Basic usage

This example demonstrates creating a custom SeekableIterator, seeking to a position and handling an invalid position.

`<?php
class MySeekableIterator implements SeekableIterator {
private $position;
private $array = array(
"first element",
"second element",
"third element",
"fourth element"
);
/* Method required for SeekableIterator interface */
public function seek($position) {
if (!isset($this->array[$position])) {
throw new OutOfBoundsException("invalid seek position ($position)");
}
$this->position = $position;
}
/* Methods required for Iterator interface */
public function rewind() {
$this->position = 0;
}
public function current() {
return $this->array[$this->position];
}
public function key() {
return $this->position;
}
public function next() {
++$this->position;
}
public function valid() {
return isset($this->array[$this->position]);
}
}
try {
$it = new MySeekableIterator;
echo $it->current(), "\n";
$it->seek(2);
echo $it->current(), "\n";
$it->seek(1);
echo $it->current(), "\n";
$it->seek(10);
} catch (OutOfBoundsException $e) {
echo $e->getMessage();
}
?>`

The above example will output something similar to:

    first element
    third element
    second element
    invalid seek position (10)

## Table of Contents

- SeekableIterator::seek — Seeks to a position