(PHP 5 >= 5.1.0, PHP 7, PHP 8)
Countable::count — 计算对象的元素个数
此函数没有参数。
示例 #1 Countable::count() 示例
<?php
class myCounter implements Countable {
private $count = 0;
public function count() {
return ++$this->count;
}
}
$counter = new myCounter;
for($i=0; $i<10; ++$i) {
echo "我已被 count() 调用了 " . count($counter) . " 次\n";
}
?>以上示例将输出类似以下内容
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
即使在 count() 函数中使用实现 Countable 接口的对象时会调用 Countable::count 方法，count 的第二个参数 $mode 也不会影响您的类方法。
$mode 不会传递给 Countable::count
<?php
class Foo implements Countable
{
public function count()
{
var_dump(func_get_args());
return 1;
}
}
count(new Foo(), COUNT_RECURSIVE);
?>
var_dump 输出
array(0) {
}