(PHP 5 >= 5.1.0, PHP 7, PHP 8)
iterator_to_array — Copia un iterador en un array
Copia los elementos de un iterador en un array .
iteratorEl iterador a copiar.
preserve_keysSi se deben utilizar los elementos del iterador como clave.
Si una clave es un array o un
object , se generará una advertencia. Las claves null serán
convertidas en una cadena vacía, las claves de tipo float
serán truncadas a sus partes int , las claves
de tipo resource generarán una advertencia y serán convertidas
en identificador de la recurso, y las claves de tipo bool
serán convertidas en enteros.
Nota:
Si este argumento no está definido o está definido en
true, las claves duplicadas serán sobrescritas. El último valor con una clave dada estará en el array devuelto. Definir este argumento enfalsepara obtener todas las valores en todo caso.
Un array que contiene los elementos del iterador
iterator.
| Versión | Descripción |
|---|---|
| 8.2.0 |
El tipo de iterator ha sido ampliado de
Traversable a
Traversable |array .
|
Ejemplo #1 Ejemplo con iterator_to_array()
<?php
$iterator = new ArrayIterator(array('recipe'=>'crêpes', 'oeufs', 'lait', 'farine'));
var_dump(iterator_to_array($iterator, true));
var_dump(iterator_to_array($iterator, false));
?>El ejemplo anterior mostrará:
array(4) {
["recipe"]=>
string(7) "crêpes"
[0]=>
string(5) "oeufs"
[1]=>
string(4) "lait"
[2]=>
string(6) "farine"
}
array(4) {
[0]=>
string(7) "crêpes"
[1]=>
string(5) "oeufs"
[2]=>
string(4) "lait"
[3]=>
string(6) "farine"
}
One important thing to remember is that in iterator can be infinite. Not all iterators necessarily end. If iterator_to_array is used on such an iterator, it will exhaust the available memory, and throw a fatal error.
For example, consider the following code:
<?php
function fibonacci(): Generator
{
yield $a = 1;
yield $b = 2;
start:
yield $c = $a + $b;
$a = $b;
$b = $c;
goto start;
}
$fibonacciSequence = fibonacci();
iterator_to_array($fibonacciSequence);
?>
Since <?php fibonacci(); ?> generates an infinite fibonacci sequence, which is valid, since it is actually an infinite sequence, then attempting to convert it to an array will fail.Using the boolean param :
<?php
$first = new ArrayIterator( array('k1' => 'a' , 'k2' => 'b', 'k3' => 'c', 'k4' => 'd') );
$second = new ArrayIterator( array( 'k1' => 'X', 'k2' => 'Y', 'Z' ) );
$combinedIterator= new AppendIterator();
$combinedIterator->append( $first );
$combinedIterator->append( $second );
var_dump( iterator_to_array($combinedIterator, false) );
?>
will output :
array(7) (
[0]=>
string(1) "a"
[1]=>
string(1) "b"
[2]=>
string(1) "c"
[3]=>
string(1) "d"
[4]=>
string(1) "X"
[5]=>
string(1) "Y"
[6]=>
string(1) "Z"
)
<?php
var_dump( iterator_to_array($combinedIterator, true) );
?>
will output (since keys would merge) :
array(5) (
["k1"]=>
string(1) "X"
["k2"]=>
string(1) "Y"
["k3"]=>
string(1) "c"
["k4"]=>
string(1) "d"
[0]=>
string(1) "Z"
)To generate an deep array from nested iterators:
<?php
function iterator_to_array_deep(\Traversable $iterator, $use_keys = true) {
$array = array();
foreach ($iterator as $key => $value) {
if ($value instanceof \Iterator) {
$value = iterator_to_array_deep($value, $use_keys);
}
if ($use_keys) {
$array[$key] = $value;
} else {
$array[] = $value;
}
}
return $array;
}
?>
I use it to test an iterator: https://gist.github.com/jm42/cb328106f393eeb28751 When using iterator_to_array() on an SplObjectStorage object, it's advisable to set $use_keys to false.
The resulting array is identical, since the iterator keys produced by SplObjectStorage::key() are always integers from 0 to (COUNT-1). Passing $use_keys=false cuts out the unnecessary calls to SplObjectStorage::key(), giving a slight performance advantage.