Can be used to iterate through recursive iterators.
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.
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
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", $directory);
}
?>
Note: if there is a directory contained within the directory you are searching in that you have no access to read an UnexpectedValueException will be thrown (leaving you with an empty list).
Note: objects returned are SPLFileObjects
Recursive multidimensional array flatten using SPL
<?php
function array_flatten_recursive($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
)