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<RecursiveCachingIterator::hasChildrenRecursiveCallbackFilterIterator::__construct>
^IteratorsLast updated: Mon, 26 Oct 2026

The RecursiveCallbackFilterIterator class

(PHP 5 >= 5.4.0, PHP 7, PHP 8)

Introduction

Class synopsis

class RecursiveCallbackFilterIterator extends CallbackFilterIterator implements RecursiveIterator {
/* Methods */
public function __construct(RecursiveIterator $iterator, callable $callback)
public function hasChildren(): bool
/* Inherited methods */
public function FilterIterator::accept(): bool
public function FilterIterator::current(): mixed
public function FilterIterator::key(): mixed
public function FilterIterator::next(): void
public function FilterIterator::rewind(): void
public function FilterIterator::valid(): bool
public function IteratorIterator::current(): mixed
public function IteratorIterator::key(): mixed
public function IteratorIterator::next(): void
public function IteratorIterator::rewind(): void
public function IteratorIterator::valid(): bool
}

Examples

The callback should accept up to three arguments: the current item, the current key and the iterator, respectively.

Example #1 Available callback arguments

<?php

/**
 * Callback for RecursiveCallbackFilterIterator
 *
 * @param $current   Current item's value
 * @param $key       Current item's key
 * @param $iterator  Iterator being filtered
 * @return boolean   TRUE to accept the current item, FALSE otherwise
 */
function my_callback($current, $key, $iterator) {
    // Your filtering code here
}

?>

Filtering a recursive iterator generally involves two conditions. The first is that, to allow recursion, the callback function should return true if the current iterator item has children. The second is the normal filter condition, such as a file size or extension check as in the example below.

Example #2 Recursive callback basic example

<?php

$dir = new RecursiveDirectoryIterator(__DIR__);

// Filter large files ( > 100MB)
$files = new RecursiveCallbackFilterIterator($dir, function ($current, $key, $iterator) {
    // Allow recursion
    if ($iterator->hasChildren()) {
        return TRUE;
    }
    // Check for large file
    if ($current->isFile() && $current->getSize() > 104857600) {
        return TRUE;
    }
    return FALSE;
});
 
foreach (new RecursiveIteratorIterator($files) as $file) {
    echo $file->getPathname() . PHP_EOL;
}

?>

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<RecursiveCachingIterator::hasChildrenRecursiveCallbackFilterIterator::__construct>
^IteratorsLast updated: Mon, 26 Oct 2026