Countable::count

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

Countable::count — 统计对象的元素个数

说明

public Countable::count(): int

当 count() 的 value 是实现 Countable 的对象时，会执行此方法。

参数

此函数没有参数。

返回值

int 形式的自定义计数。

示例

示例 #1 Countable::count() 示例

<?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 "I have been count()ed " . count($counter) . " times\n";
}

?>

以上示例的输出类似于：

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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SenseException ¶

10 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:

<?php

class Foo implements Countable
{
    public function count()
    {
var_dump(func_get_args());
        return 1;
    }
}

count(new Foo(), COUNT_RECURSIVE);

?>

var_dump output:

array(0) {
}