iterator_count

(PHP 5 >= 5.1.0)

iterator_count — Count the elements in an iterator

Opis

int iterator_count ( Traversable $iterator )

Count the elements in an iterator.

Parametry

iterator: The iterator being counted.

Zwracane wartości

The number of elements in iterator.

Przykłady

Przykład #1 iterator_count() example


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

Powyższy przykład wyświetli:

int(4)

iterator_to_array

iterator_apply

[edit] Last updated: Fri, 23 Mar 2012

add a note User Contributed Notes iterator_count

donovan jimenez 23-Feb-2009 09:34


Be careful of thinking of iterators and arrays as completely analogous in your PHP code. iterator_count will NOT return your iterator to its previous state after looping through it for the count. Any iterator implementation that also implements Countable::count isn't required to do so either.



This is clearest in example form:

<?php

$array = array(

    1 => 'foo',

    2 => 'bar'

);



foreach ($array as $key => $value)

{

    echo "$key: $value (", count($array), ")\n";

}



$iterator = new ArrayIterator($array);



foreach ($iterator as $key => $value)

{

    echo "$key: $value (", iterator_count($iterator), ")\n";

}

?>



outputs:

1: foo (2)

2: bar (2)

1: foo (2)



Notice that because of how iterator_count works we never see the second iterator value because the next call to then Iterator::valid() implementation returns false (its at the end of the iterator).

Micha Mech 09-May-2008 03:38


Yes, but ...



Traversable: "Abstract base interface that cannot be implemented alone. Instead it must be implemented by either IteratorAggregate or Iterator."



So You have to implement IteratorAggregate or Iterator because You can not implement Traversable.

Ard 31-Aug-2006 03:39


Note that you that the iterator parameter doesn't need to be of type Aggregate. As the spl documentation on http://www.php.net/~helly/php/ext/spl/ defines it in the following way:



    iterator_count (Traversable $it).



So you can count the number of files in a given directory quite easily:

<?php iterator_count(new DirectoryIterator('path/to/dir/'));    ?>

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