PHP - Manual: iterator_to_array

2024-11-15

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iterator_to_array

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

iterator_to_array — 将迭代器中的元素拷贝到数组

说明

iterator_to_array(Traversable $iterator, bool $use_keys = true): array

将迭代器中的元素拷贝到数组。

参数

iterator: 被拷贝的迭代器。
use_keys: 是否使用迭代器元素键作为索引。

返回值

一个数组，包含迭代器中的元素。

更新日志

版本	说明
5.2.1	添加了 `use_keys` 参数。

范例

示例 #1 iterator_to_array() example


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

以上例程会输出：

array(4) {
  ["recipe"]=>
  string(8) "pancakes"
  [0]=>
  string(3) "egg"
  [1]=>
  string(4) "milk"
  [2]=>
  string(5) "flour"
}
array(4) {
  [0]=>
  string(8) "pancakes"
  [1]=>
  string(3) "egg"
  [2]=>
  string(4) "milk"
  [3]=>
  string(5) "flour"
}

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User Contributed Notes 6 notes

down

jerome at yazo dot net ¶

13 years ago


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"

)

down

joksnet at gmail dot com ¶

7 years ago


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

down

Harry Willis ¶

7 years ago


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.

down

wizzard351 at yahoo dot com ¶

3 months ago


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.

down

-2

enelar at develop-project dot ru ¶

5 years ago


Generator approach

function scandir_deep($dir)
{
  foreach (scandir($dir) as $key => $value)
    if (in_array($value, [".",".."]))
      continue;
    else if (is_dir($dir . DIRECTORY_SEPARATOR . $value))
      yield $value => scandir_deep($dir . DIRECTORY_SEPARATOR . $value);
    else
      yield $value;
}

down

-4

chad 0x40 herballure 0x2e com ¶

14 years ago


The use_keys parameter was added in one of the 5.2.x releases; it defaults to TRUE. This matches the behavior in PHP 5.1.6, which lacks this parameter.

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官方地址：https://www.php.net/manual/en/function.iterator-to-array.php

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iterator_to_array

说明

参数

返回值

更新日志

范例

User Contributed Notes 6 notes