ArrayIterator::seek

(PHP 5, PHP 7, PHP 8)

ArrayIterator::seek — Seek to position

说明

public ArrayIterator::seek ( int $offset ) : void

Warning

本函数还未编写文档，仅有参数列表。

参数

offset: The position to seek to.

返回值

没有返回值。

User Contributed Notes

foalford at gmail dot com 27-Apr-2016 02:20


<?php

//seek alter the iterator's internal indice instead of the value that key() returns. 

//This is a big trap if combining with uasort/natsort function. 



$a = new ArrayObject([4,3,2,1]);

$it = $a->getIterator();

$it->natsort();   //The Iterator preserve the key while sorting the array 

$it->rewind();

$first = $it->key();   //The first element is  1 and it's key is 3

echo $first. PHP_EOL;  // 3



$it->next();

$second = $it->key();

echo $second. PHP_EOL; //2



$it->next();

$it->seek($first);             //Was intended to seek to element 1, key 3, indice 0

echo  $it->key() . PHP_EOL; //end up 0 because seek took parameter as indice instead of key. It seek to element indice 3, element 4 key 0.



var_dump($it);



/* Output: 

3

2

0

object(ArrayIterator)#2 (1) {

  ["storage":"ArrayIterator":private]=>

  object(ArrayObject)#1 (1) {

    ["storage":"ArrayObject":private]=>

    array(4) {

      [3]=>

      int(1)

      [2]=>

      int(2)

      [1]=>

      int(3)

      [0]=>

      int(4)

    }

  }

}

*/

jon at ngsthings dot com 21-Oct-2008 05:08


<?php

// didn't see any code demos...here's one from an app I'm working on



$array = array('1' => 'one',

               '2' => 'two',

               '3' => 'three');



$arrayobject = new ArrayObject($array);

$iterator = $arrayobject->getIterator();



if($iterator->valid()){

    $iterator->seek(1);            // expected: two, output: two

    echo $iterator->current();    // two

}



?>