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    The CallbackFilterIterator class

    (PHP 5 >= 5.4.0, PHP 7)

    소개

    클래스 개요

    CallbackFilterIterator extends FilterIterator implements OuterIterator {
    /* 메소드 */
    public __construct ( Iterator $iterator , callable $callback )
    public string accept ( void )
    /* 상속된 메소드 */
    public abstract bool FilterIterator::accept ( void )
    public FilterIterator::__construct ( Iterator $iterator )
    public mixed FilterIterator::current ( void )
    public Iterator FilterIterator::getInnerIterator ( void )
    public mixed FilterIterator::key ( void )
    public void FilterIterator::next ( void )
    public void FilterIterator::rewind ( void )
    public bool FilterIterator::valid ( void )
    }

    예제

    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();
    });

    ?>

    Table of Contents

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    User Contributed Notes 3 notes

    up
    10
    dave1010 at gmail dot com
    12 years ago
    Implementation for PHP < 5.4:

    <?php
    if (!class_exists('CallbackFilterIterator')) {   
        class     CallbackFilterIterator extends FilterIterator {
            protected     $callback;

                // "Closure" type hint should be "callable" in PHP 5.4
                public function __construct(Iterator $iterator, Closure $callback = null) {
                    $this->callback = $callback;
                    parent::__construct($iterator);
            }

            public function     accept() {
                return     call_user_func(
                        $this->callback,
                        $this->current(),
                        $this->key(),
                        $this->getInnerIterator()
                );
            }
        }
    }

    ?>
    up
    2
    asadi dot jabar at outlook dot com
    6 years ago
    CallbackFilterIterator class  didnot implement   OuterIterator interface directly

    below  is the correct hierarchy

    CallbackFilterIterator 
              |__FilterIterator
                 |___  IteratorIterator
                     |____ OuterIterator

    please fix the documentation
    up
    1
    tunaabutbul[plus]php[at]gmail[dot]com
    7 years ago
    i PHP 7 you can use Anonymous classes to get the same results.

    <?php

    class MyIterator implements Iterator
    {
            /**
         * @var \Iterator
         */
            protected $next;

            /**
         * Collection constructor.
         *
         * @param \Iterator $next
         */
            public function __construct(Iterator $next)
        {
                $this->next = $next;
        }

            /**
         * @param callable $callback
         *
         * @return static
         */
            public function filter(callable $callback = null)
        {
            return new static(new class(    $this, $callback) extends FilterIterator
                {
                protected     $callback;

                public function     __construct(\Iterator $iterator, callable $callback = null)
                {
                        parent::__construct($iterator);

                        $this->callback = $callback ?: function($current) {
                        return ! empty(    $current);
                    };;
                }

                public function     accept()
                {
                    return     call_user_func($this->callback, parent::accept());
                }
            });
        }
           // Iterator methods ...
    }
    // .......
    ?>
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