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The RecursiveIteratorIterator class

(PHP 5)

简介

Can be used to iterate through recursive iterators.

类摘要

RecursiveIteratorIterator implements OuterIterator , Traversable , Iterator {
/* Constants */
const integer LEAVES_ONLY = 0 ;
const integer SELF_FIRST = 1 ;
const integer CHILD_FIRST = 2 ;
const integer CATCH_GET_CHILD = 16 ;
/* 方法 */
public void beginChildren ( void )
public void beginIteration ( void )
public RecursiveIterator callGetChildren ( void )
public bool callHasChildren ( void )
public __construct ( Traversable $iterator [, int $mode = RecursiveIteratorIterator::LEAVES_ONLY [, int $flags = 0 ]] )
public mixed current ( void )
public void endChildren ( void )
public void endIteration ( void )
public int getDepth ( void )
public iterator getInnerIterator ( void )
public mixed getMaxDepth ( void )
public RecursiveIterator getSubIterator ( void )
public mixed key ( void )
public void next ( void )
public void nextElement ( void )
public void rewind ( void )
public void setMaxDepth ([ string $max_depth = -1 ] )
public bool valid ( void )
/* 继承的方法 */
public Iterator OuterIterator::getInnerIterator ( void )
}

预定义常量

RecursiveIteratorIterator::LEAVES_ONLY

RecursiveIteratorIterator::SELF_FIRST

RecursiveIteratorIterator::CHILD_FIRST

RecursiveIteratorIterator::CATCH_GET_CHILD

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PHP手册 - N: The RecursiveIteratorIterator class

用户评论:

Adil Baig @ AIdezigns (24-Jun-2011 07:17)

A very important thing to note about \RecursiveIteratorIterator is that it returns a flattened array when used with the iterator_to_array function. Ex:

<?php
$arr = array('Zero', 'name'=>'Adil', 'address' => array( 'city'=>'Dubai', 'tel' => array('int' => 971, 'tel'=>12345487)), '' => 'nothing');

$iterator = new \RecursiveIteratorIterator(new \RecursiveArrayIterator($arr));
var_dump(iterator_to_array($iterator,true));
?>

This code will return :

array(6) {
  [0]=>
  string(4) "Zero"
  ["name"]=>
  string(4) "Adil"
  ["city"]=>
  string(5) "Dubai"
  ["int"]=>
  int(91)
  ["tel"]=>
  int(12345487)
  [""]=>
  string(7) "nothing"
}

To get the non-flattened proper array use the getArrayCopy() method, like so :

$iterator->getArrayCopy()

This will return

array(4) {
  [0]=>
  string(4) "Zero"
  ["name"]=>
  string(4) "Adil"
  ["address"]=>
  array(2) {
    ["city"]=>
    string(5) "Dubai"
    ["tel"]=>
    array(2) {
      ["int"]=>
      int(91)
      ["tel"]=>
      int(12345487)
    }
  }
  [""]=>
  string(7) "nothing"
}

Tom (06-Jan-2011 09:35)

This class operates on a tree of elements, which is build by nesting recursive iterators into one another.

Thus you might say it is an iterator over iterators. While traversing those, the class pushes the iterators on a stack while traversing down to a leaf and removes them from the stack while going back up.

aidan at php dot net (30-Apr-2010 05:57)

This example demonstrates using the getDepth() method with a RecursiveArrayIterator.

<?php
$tree = array();
$tree[1][2][3] = 'lemon';
$tree[1][4] = 'melon';
$tree[2][3] = 'orange';
$tree[2][5] = 'grape';
$tree[3] = 'pineapple';

print_r($tree);
 
$arrayiter = new RecursiveArrayIterator($tree);
$iteriter = new RecursiveIteratorIterator($arrayiter);
 
foreach ($iteriter as $key => $value) {
  $d = $iteriter->getDepth();
  echo "depth=$d k=$key v=$value\n";
}
?>

The output of this would be:

Array
(
    [1] => Array
        (
            [2] => Array
                (
                    [3] => lemon
                )

            [4] => melon
        )

    [2] => Array
        (
            [3] => orange
            [5] => grape
        )

    [3] => pineapple
)

depth=2 k=3 v=lemon
depth=1 k=4 v=melon
depth=1 k=3 v=orange
depth=1 k=5 v=grape
depth=0 k=3 v=pineapple

Michiel Brandenburg (15-Jun-2009 12:40)

You can use this to quickly find all the files (recursively) in a certain directory. This beats maintaining a stack yourself.
<?php
$directory = "/tmp/";
$fileSPLObjects =  new RecursiveIteratorIterator(
                new RecursiveDirectoryIterator($directory),
                RecursiveIteratorIterator::CHILD_FIRST
            );
try {
    foreach( $fileSPLObjects as $fullFileName => $fileSPLObject ) {
        print $fullFileName . " " . $fileSPLObject->getFilename() . "\n";
    }
}
catch (UnexpectedValueException $e) {
    printf("Directory [%s] contained a directory we can not recurse into", $directory);
}
?>
Note: if there is a directory contained within the directory you are searching in that you have no access to read an UnexpectedValueException will be thrown (leaving you with an empty list).
Note: objects returned are SPLFileObjects

crashrox at gmail dot com (19-Dec-2008 05:51)

Recursive multidimensional array flatten using SPL

<?php
function array_flatten_recursive($array) {
    if($array) {
        $flat = array();
        foreach(new RecursiveIteratorIterator(new RecursiveArrayIterator($array), RecursiveIteratorIterator::SELF_FIRST) as $key=>$value) {
            if(!is_array($value)) {
                $flat[] = $value;
            }
        }
       
        return $flat;
    } else {
        return false;
    }
}

$array = array(
    'A' => array('B' => array( 1, 2, 3, 4, 5)),
    'C' => array( 6,7,8,9)
);

print_r(array_flatten_recursive($array));
?>
-- Returns:
Array (
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
    [6] => 7
    [7] => 8
    [8] => 9
)