if not statement

is this an if not statement:

if!()
{
}

if not how do you do it? I'm trying to make a folder if the folder doesn't exist.

 

if (!isset($var)) { }

or

if (empty($var)) {}

or

if (!something) {}

Code (markup):

or so

 

Try this:

if(!file_exists("foobar"))
{
        mkdir("foobar");
}

PHP:

Thomas

 

Just move the ! inside the parentheses.

 

yes ! shuld be infront and in parentheses. like


if(!$var)

{

do something

}