Php manual, How to solve it

Php manual http://php.net/manual/zh/function.isset.php code &lt ;? Php $ var & nbsp ;=& nbsp; ''; // & nbsp; the result is & nbsp; TRUE, so the subsequent text will be printed. If & nbsp; php Manual
Http://php.net/manual/zh/function.isset.php

Code

$ Var = '';

// The result is TRUE, so the subsequent text is printed.
If (isset ($ var )){
Echo "This var is set so I will print .";
}

// In the following example, var_dump is used to output the return value of isset.
// The return value of isset ().

$ A = "test ";
$ B = "anothertest ";

Var_dump (isset ($ a); // TRUE
Var_dump (isset ($ a, $ B); // TRUE

Unset ($ );

Var_dump (isset ($ a); // FALSE
Var_dump (isset ($ a, $ B); // What is the role of B here? B does not seem to have been destroyed.

$ Foo = NULL;
Var_dump (isset ($ foo); // FALSE

?>

Var_dump (isset ($ a, $ B); // What is the role of B here? B does not seem to have been destroyed. Share: More