<?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)
}
}
}
*/