Countable::count

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

    Countable::count — Подсчитывает количество элементов в объекте

    Описание

    public Countable::count(): int

    Метод выполняется, когда в параметр value функции count() передают объект, класс которого реализует интерфейс Countable.

    Список параметров

    У этой функции нет параметров.

    Возвращаемые значения

    Метод возвращает пользовательское количество элементов объекта в виде значения с типом int.

    Примеры

    Пример #1 Пример подсчёта элементов объекта методом Countable::count()

    <?php

    class Counter implements Countable
    {
    private     $count = 0;

    public function     count(): int
    {
    return ++    $this->count;
    }
    }

    $counter = new Counter();

    for (    $i = 0; $i < 10; ++$i) {
    echo     "Вот сколько раз меня посчитали функций count(): ", count($counter), "\n";
    }

    ?>

    Вывод приведённого примера будет похож на: 

    I have been count()ed 1 times
I have been count()ed 2 times
I have been count()ed 3 times
I have been count()ed 4 times
I have been count()ed 5 times
I have been count()ed 6 times
I have been count()ed 7 times
I have been count()ed 8 times
I have been count()ed 9 times
I have been count()ed 10 times

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    Примечания пользователей 2 notes

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    13
    SenseException
    11 years ago
    Even though Countable::count method is called when the object implementing Countable is used in count() function, the second parameter of count, $mode, has no influence to your class method. $mode is not passed to  Countable::count:<?phpclass Foo implements Countable{    public function count()    {        var_dump(func_get_args());        return 1;    }}count(new Foo(), COUNT_RECURSIVE);?>var_dump output:array(0) {}
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    1
    moris at moris dot org dot ua
    4 months ago
    First, the commonly referenced example of Countable is somewhat misleading from an OOP perspective, as it unintentionally violates some key principles. While it demonstrates the concept of Countable, it does so in a way that could cause confusion.According to the Countable interface:<?php/** * Count elements of an object * @link https://php.net/manual/en/countable.count.php * @return int<0,max> The custom count as an integer. * <p> * The return value is cast to an integer. * </p> */#[TentativeType]public function count(): int;?>This means that the `count()` method should not modify the state of an object—it should simply return an integer value, aligning with SOLID principles.  A proper OOP approach would be:  <?phpclass Counter implements Countable{    private $count = 0;    // Returns the item count of the object    public function count(): int    {        return $this->count;    }    public function increment(): void    {        $this->count++;    }}$counter = new Counter;for ($i = 0; $i < 10; ++$i) {    $counter->increment();    echo "I have been incremented " . count($counter) . " times\n";}?>Here, count() correctly returns the number of elements, while increment() is responsible for modifying the state of the object.A separate discussion can be had about whether to use count($object) or $object->count(), but that’s a different topic.
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