(PHP 7 >= 7.3.0, PHP 8)
is_countable — 验证变量内容是否为可数值
value需要检查的值
| 版本 | 说明 |
|---|---|
| 7.3.0 | is_countable() 被添加。 |
示例 #1 is_countable() 示例
<?php
var_dump(is_countable([1, 2, 3])); // bool(true)
var_dump(is_countable(new ArrayIterator(['foo', 'bar', 'baz']))); // bool(true)
var_dump(is_countable(new ArrayIterator())); // bool(true)
var_dump(is_countable(new stdClass())); // bool(false)
If you are unable to upgrade to PHP 7.3 (not released at the time of writing), you can use this simple polyfill:
<?php
if (!function_exists('is_countable')) {
function is_countable($var) {
return (is_array($var) || $var instanceof Countable);
}
}
?>be wary of using is_object($var) and assuming that the object has implemented Countable. Not all objects are countable directly with count().Note that a polyfill for this method is also provided by the symfony/polyfill project.