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    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
    }

    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)

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