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    iterator_to_array

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

    iterator_to_array — Copy the iterator into an array

    Description

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

    Copy the elements of an iterator into an array.

    Parameters

    iterator

    The iterator being copied.

    preserve_keys

    Whether to use the iterator element keys as index.

    If a key is an array or object, a warning will be generated. null keys will be converted to an empty string, float keys will be truncated to their int counterpart, resource keys will generate a warning and be converted to their resource ID, and bool keys will be converted to integers.

    Note:

    If this parameter is not set or set to true, duplicate keys will be overwritten. The last value with a given key will be in the returned array. Set this parameter to false to get all the values in any case.

    Return Values

    An array containing the elements of the iterator.

    Changelog

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

    Examples

    Example #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));
    ?>

    The above example will output:

    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

    up
    4
    wizzard351 at yahoo dot com
    2 years 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.
    up
    6
    jerome at yazo dot net
    16 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"
    )
    up
    4
    joksnet at gmail dot com
    10 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
    up
    3
    Harry Willis
    9 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.
    up
    -5
    chad 0x40 herballure 0x2e com
    16 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.
    up
    -3
    enelar at develop-project dot ru
    7 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;
    }
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