判断PHP数据类型

常用方式：is_int(), is_float()l, is_numeric(), is_array()...

另一种更快捷的方式：用 === 或 !== ，即全等和不全等运算符来判断。

I‘ve found a faster way of determining an array. If you use is_array() millions of times, you will notice a *huge* difference. On my machine, this method takes about 1/4 the time of using is_array().
Cast the value to an array, then check (using ===) if it is identical to the original. 
<?php 
if ( (array) $unknown !== $unknown ) { 
    echo ‘$unknown is not an array‘; 
} else { 
    echo ‘$unknown is an array‘; 
} 
?>

http://php.net/manual/zh/function.is-array.php