iterator_to_array()

(PHP 5 >= 5.1.0, PHP 7)

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

范例

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"
}

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

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"
)

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;
}

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.

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.