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  • Countable::count()

    (PHP 5 >= 5.1.0, PHP 7)

    统计一个对象的元素个数

    说明

    abstractpublicCountable::count(void): int

    当使用count()函数作用于一个实现了Countable的对象时这个方法会被执行.

    参数

    此函数没有参数。

    返回值

    The custom count as an integer.

    Note:

    The return value is cast to an integer.

    范例

    Countable::count() example

    <?php
    class myCounter implements Countable {
        public function count() {
            static $count = 0;
            return ++$count;
        }
    }
    $counter = new myCounter;
    for($i=0; $i<10; ++$i) {
        echo "I have been count()ed " . count($counter) . " times\n";
    }
    ?>
    

    以上例程的输出类似于:

    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
    
    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) {
    }