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    iterator_apply

    (PHP 5 >= 5.1.0, PHP 7, PHP 8)

    iterator_apply — Llamar a una función para cada elemento de un iterador

    Descripción

    iterator_apply(Traversable $iterator, callable $function, array $args = ?): int

    Llama a una función para cada elemento de un iterador.

    Parámetros

    iterator

    La clase a recorrer.

    function

    La función de llamada de retorno a invocar para cada elemento.

    Nota: Esta función debe retornar true para continuar recorriendo el iterator.

    args

    Argumentos a pasar a la función de llamada de retorno.

    Valores devueltos

    Devuelve el número de iteraciones.

    Ejemplos

    Ejemplo #1 Ejemplo de iterator_apply()

    <?php
    function print_caps(Iterator $iterator) {
    echo     strtoupper($iterator->current()) . "\n";
    return     TRUE;
    }

    $it = new ArrayIterator(array("Manzanas", "Bananas", "Cerezas"));
    iterator_apply($it, "print_caps", array($it));
    ?>

    El resultado del ejemplo sería:

    MANZANAS
BANANAS
CEREZAS

    Ver también

    • array_walk() - Aplicar una función proporcionada por el usuario a cada miembro de un array

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    User Contributed Notes 3 notes

    up
    2
    tezcatl at fedoraproject dot org
    6 years ago
    Each of the arguments required by the function, must be in the array supplied in the third argument to iterator_apply. You can use references too. Example:

    <?php

    function translate_to(string $target_language, Iterator $words, array $dictionaries) {
       
            $language = ucfirst($target_language);
            $dictionary = $dictionaries[$target_language] ?? 'not found';
       
        if (    $dictionary === 'not found') {
            echo     "Not found dictionary for {$language}\n";
            return;
        }
       
        echo     "English words translated to {$language}\n";
       
            $not_found = [];
       
            iterator_apply($words, function($words, $dictionary, &$not_found){
       
                $english_word = $words->current();
       
                $translated_word = $dictionary[$english_word] ?? '';
       
            if (    $translated_word !== '') {
                echo     "{$english_word} translates to {$translated_word}\n";
            } else {
                    $not_found[] = $english_word;
            }

            return     true;
       
        }, array(    $words, $dictionary, &$not_found));
       
        echo     "\nNot found words:\n" . implode("\n", $not_found) . "\n";
    }

    $dictionaries = [
            'nahuatl' => [
                'one' => 'Ze',
                'two' => 'Ome',
                'three' => 'Yei',
                'four' => 'Nahui',
        ],
    ];

    $iterator = new \ArrayIterator(array('one', 'two', 'three', 'four', 'gasoil'));

    translate_to('nahuatl', $iterator, $dictionaries);
    ?>

    English words translated to Nahuatl
    one translates to Ze
    two translates to Ome
    three translates to Yei
    four translates to Nahui

    Not found words:
    gasoil
    up
    1
    tezcatl at fedoraproject dot org
    6 years ago
    Be aware of the proper methods to iterate the specific Iterator you are consuming, as the implementation of the method could vary its behaviour.

    For example, unlike the ArrayIterator, you can't iterate on a SplDoubleLinkedList with current() without using next() on every iteration (and then, only would iterate if you return true at the end of the callable. It is far easier then with LinkedLists use a while($it->valid()) { $it->current(); $it->next(); }

    Let's see:

    <?php

    $ll     = new \SplDoublyLinkedList();

    $ll->push('ze');
    $ll->push('ome');
    $ll->push('yei');
    $ll->push('nahui');

    $ll->rewind();

    $iterations_done = iterator_apply($ll, function(Iterator $it) {

        echo     implode("\t=>", [
                $it->key(),
                $it->current(),
                ucfirst($it->current())
        ]),    "\n";
       
        return     true;

    }, array(    $ll));

    echo     "Did iterate {$iterations_done} times \n";

    $ll->rewind();

    $iterations_done = iterator_apply($ll, function(Iterator $it) {

        echo     implode("\t=>", [
                $it->key(),
                $it->current(),
                ucfirst($it->current())
        ]),    "\n";
       
            $it->next();
       
        return     true;

    }, array(    $ll));

    echo     "Did iterate {$iterations_done} times \n";

    $ll->setIteratorMode(SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_DELETE);

    var_dump($ll->count());

    foreach(    $ll as $key => $val) {
        echo     "{$key}\t",ucfirst($val),"\n";
    }

    var_dump($ll->count());
    ?>

    Output:

    0    =>ze    =>Ze
    0    =>ze    =>Ze
    0    =>ze    =>Ze
    0    =>ze    =>Ze
    Did iterate 4 times
    0    =>ze    =>Ze
    1    =>ome    =>Ome
    2    =>yei    =>Yei
    3    =>nahui    =>Nahui
    Did iterate 4 times
    int(4)
    0    Ze
    0    Ome
    0    Yei
    0    Nahui
    int(0)
    up
    -2
    ycgambo at outlook dot com
    7 years ago
    $args is an array and each of its elements are passed to the callback as separate arguments.

    so this is the right way to get args:

    <?php
    $ai     = new ArrayIterator(range(0, 2));

    iterator_apply($ai, function() {
            var_dump(func_get_args());     // use this func
            return true;
    }, array(    1, 2));
    ?>

    output:

    array(2) {
      [0] =>
      int(1)
      [1] =>
      int(2)
    }
    array(2) {
      [0] =>
      int(1)
      [1] =>
      int(2)
    }
    array(2) {
      [0] =>
      int(1)
      [1] =>
      int(2)
    }

    --------------------------------------------------
    or list each args:

    <?php
    $ai     = new ArrayIterator(range(0, 2));

    iterator_apply($ai, function($arg1, $arg2, $arg3) {
            var_dump([$arg1, $arg2, $arg3]);
        return     true;
    }, array(    1, 2));
    ?>

    same output.
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