The SeekableIterator interface

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- SeekableIterator::seek »

- PHP Manual
- Interfaces
- The SeekableIterator interface

# The SeekableIterator interface

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

## Introduction

The Seekable iterator.

## Interface synopsis

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

## Examples

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