php教程

The RecursiveCallbackFilterIterator class

(PHP 5 >= 5.4.0, PHP 7)

简介

类摘要

RecursiveCallbackFilterIterator extends CallbackFilterIterator implements OuterIterator , RecursiveIterator {
/* 方法 */
public __construct ( RecursiveIterator $iterator , string $callback )
public hasChildren ( void ) : bool
/* 继承的方法 */
public CallbackFilterIterator::accept ( void ) : bool
}

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

/**
 * 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;
}

?>

Table of Contents

User Contributed Notes

a dot belloundja at gmail dot com 01-Jan-2013 11:26
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);
       
    }
   
}

?>
Anonymous 11-Dec-2011 01:31
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;
}
?>

CopyRight © 2008-2022 verySource.Com All Rights reserved. 京ICP备17048824号-1 京公网安备:11010502034788