定义和作用范围:用于测试一个变量是否具有值(包括0,FALSE,或者一个空字串,但不能是NULL),即:“http://localhost/?fo=”也是可以通过检测,因此不适用。但如果是“http://localhost/”参数中并不含fo参数,就可以用isset来检测,此时isset($_GET['fo'])返回false。 不适用于:该函数不适合于验证html表单中的文...
粗率来看使用isset最好,in_array比array_key_exists消耗更多的时间。 如果在数据量比较下的情况下这三者的情况基本接近,但是仍然isset是最快的。 因而在设计NILCMS的时候要考虑这方面的问题。铭记。
另一种选择是将全局变量包装在专用的数组对象中，或多或少具有合理的[]行为，这似乎适用于到处都使用“...
if(isset($_POST[myField]) && $_POST[myField] != "") { //Do my PHP code } A more efficient way of doing this is obviously to use: if(!empty($_POST[myField])) { //Do my PHP code } Just a quick tip for people struggling with this. There are two main points in this arti...
将返回 FALSE。同时要注意的是 null 字符（"\0"）并不等同于 PHP 的 NULL 常量。 对于 0、f ...
报错:Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in line 42改为这样: if ( isset($_GET['reply_id'], $_GET['reply_user']) ) { // code here } 当$a,$b都为true时,才为TRUE; ...
here small code for it.1234567bool isset(false); int a; if (isset==false) { cin>>a; isset=true; } Feb 26, 2012 at 3:37pm ResidentBiscuit (4459) I don't really see what you're trying to do. In c++, a variable is always "set". At least for primitive types. Granted it ...
你不需要isset, 如果$result->num_rows > 0then$row['acct_type']保证被设置。您需要检查的是用户...
As databases and visitors grow, sometimes ‘old code’ doesn’t work like it use to: it takes too long or times out for exceeding the maximum time allowed by your server for PHP execution. On a MySQL table with 30,000 rows (not too many), the query was checking one column for <3 ...
I have this code that was working initially, but does not work after I restarted my computer. The error I am getting is: Warning: Illegal offset type in isset or empty in D:\xampp\htdocs\cookieboylive\classes\Session.php on line 4 There's 3 files on my site - Index, Login, Register...