iterator_count

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

iterator_count — Count the elements in an iterator

Beschreibung

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.

Parameter-Liste

iterator: The iterator being counted.

Rückgabewerte

The number of elements in iterator.

Changelog

Version	Beschreibung
8.2.0	The type of `iterator` has been widened from Traversable to Traversable\|array.

Beispiele

Beispiel #1 iterator_count() example

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

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

int(4)

Beispiel #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());
?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

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

Beispiel #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";
}?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

0: one (3)

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User Contributed Notes 2 notes

down

oleksii dot bulba at gmail dot com ¶

2 years 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)

?>

down

info at ensostudio dot ru ¶

3 years ago

Safe using:
<?php
$cnt = iterator_count(clone $iterator);
?>

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