(PHP 5 >= 5.4.0, PHP 7, PHP 8)
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 CallbackFilterIterator
*
* @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
}
?>Any callable may be used; such as a string containing a function name, an array for a method, or an anonymous function.
Example #2 Callback basic examples
<?php
$dir = new FilesystemIterator(__DIR__);
// Filter large files ( > 100MB)
function is_large_file($current) {
return $current->isFile() && $current->getSize() > 104857600;
}
$large_files = new CallbackFilterIterator($dir, 'is_large_file');
// Filter directories
$files = new CallbackFilterIterator($dir, function ($current, $key, $iterator) {
return $current->isDir() && ! $iterator->isDot();
});
?>