The RecursiveCallbackFilterIterator class
(PHP 5 >= 5.4.0)
简介
类摘要
$iterator
, string $callback
)范例
The callback should accept up to three arguments: the current item, the current key and the iterator, respectively.
Example #1 Available callback arguments
<?php
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 ;
}
?> Table of Contents
- RecursiveCallbackFilterIterator::__construct — Create a RecursiveCallbackFilterIterator from a RecursiveIterator
- RecursiveCallbackFilterIterator::getChildren — Return the inner iterator's children contained in a RecursiveCallbackFilterIterator
- RecursiveCallbackFilterIterator::hasChildren — Check whether the inner iterator's current element has children
用户评论:
[#1] a dot belloundja at gmail dot com [2013-01-01 23:26:45]
Here is a code that may implement similar functionality in PHP 5.2 or 5.3 :
<?php
class RecursiveCallbackFilterIterator extends RecursiveFilterIterator {
public function __construct ( RecursiveIterator $iterator, $callback ) {
$this->callback = $callback;
parent::__construct($iterator);
}
public function accept () {
$callback = $this->callback;
return $callback(parent::current(), parent::key(), parent::getInnerIterator());
}
public function getChildren () {
return new self($this->getInnerIterator()->getChildren(), $this->callback);
}
}
?>
[#2] Anonymous [2011-12-11 13:31:54]
Note that the following filters out both files and directories whos names start with the letter "T". The important thing here is that since the function returns false for a directory entry whos name starts with T, the directory is also not traversed recursively.
<?php
$doesntStartWithLetterT = function ($current) {
return $current->getFileName()[0] !== 'T';
};
$rdi = new RecursiveDirectoryIterator(__DIR__);
$files = new RecursiveCallbackFilterIterator($rdi, $doesntStartWithLetterT);
foreach (new RecursiveIteratorIterator($files) as $file) {
echo $file->getPathname() . PHP_EOL;
}
?>