if((!$a)||(!$b)){} ??????

i'm having trouble with an if statment
i think it has to do with some misinformation that i recieved
i was told that

if((!$a)||(!$b)){}

was

if(no $a and no $b){}

but when i run
if(isset($_POST[var_mm])){
echo "month";
}
it does not echo "month";

but when i run
if((isset($POST[var_mm]))||(empty($POST[var_yyyy]))){
echo "month, no year";
}
it echos "month, no year";

thanks for any help

You have the Distribution Property wrong, read up on something called DeMorgan's Law:

(!$a) or (!$b) // either a or b is false

is the same as

not ( $a and $b) // not (a and b both true) (i.e. one of them is false...)

i figured that was the problem, the guy who is suppos to be "teaching" me apparently doesn't konw what hes talking about

well, anyway i got around the problem by doing

if(isset($POST[var_yyyy])){
if(empty($POST[var_mm])){
}
}

but i really would like to know how i could do that with one if statment

If I'm understanding you correctly, you want to execute some code if $POST['var_yyyy'] is set and $POST['var_mm'] is empty.

So maybe something like this is what you're looking for:


if(isset($_POST['var_yyyy'])) && !isset($_POST['var_mm']))
{
     //code to execute if true
}

Becareful in the context you use isset(), will return true for a value of $v = "";

yeah, thats what i'm looking for, thanks.