International PHP Conference Berlin 2023

iterator_count

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

iterator_countCount the elements in an iterator

Description

iterator_count(Traversable|array $iterator): int

Count the elements in an iterator. iterator_count() is not guaranteed to retain the current position of the iterator.

Parameters

iterator

The iterator being counted.

Return Values

The number of elements in iterator.

Changelog

Version Description
8.2.0 The type of iterator has been widened from Traversable to Traversable|array.

Examples

Example #1 iterator_count() example

<?php
$iterator 
= new ArrayIterator(array('recipe'=>'pancakes''egg''milk''flour'));
var_dump(iterator_count($iterator));
?>

The above example will output:

int(4)

Example #2 iterator_count() modifies position

<?php
$iterator 
= new ArrayIterator(['one''two''three']);
var_dump($iterator->current());
var_dump(iterator_count($iterator));
var_dump($iterator->current());
?>

The above example will output:

string(3) "one"
int(3)
NULL

Example #3 iterator_count() in foreach loops

<?php
$iterator 
= new ArrayIterator(['one''two''three']);
foreach (
$iterator as $key => $value) {
    echo 
"$key$value ("iterator_count($iterator), ")\n";
}
?>

The above example will output:

0: one (3)

add a note

User Contributed Notes 2 notes

up
1
info at ensostudio dot ru
2 years ago
Safe using:
<?php
$cnt
= iterator_count(clone $iterator);
?>
up
1
oleksii dot bulba at gmail dot com
1 year ago
Be aware that counting over NoRewindIterator will make items unavailable:

<?php

$iterator
= new ArrayIterator(['recipe'=>'pancakes', 'egg', 'milk', 'flour']);
$iterator = new NoRewindIterator($iterator);

var_dump($iterator->current());
var_dump(iterator_count($iterator));
var_dump($iterator->current());
$iterator->rewind(); // Does not work because it's NoRewindIterator
var_dump($iterator->current());
var_dump(iterator_count($iterator));

?>

Output:

<?php

/*
string(8) "pancakes"
int(4)
NULL
NULL
*/
int(0)

?>
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