Check if $_GET["menu"] is null.

[Nuno Paquete]

Hi group.
I'm using this code to see if is there any parameter for variable "menu":

if($_GET["menu"] == "downloads" )
....

But this code log errors if there is no parameter passed (this heappens at
the first time the page is loaded).

I tryed this code:

if($_GET["menu"] != ""){
if($_GET["menu"] == "downloads" )
...

But this log the same error on the second line.
Any help hould be greattly appreciated.
Thanks in advance,

Nuno Paquete

[Zurab Davitiani]

Zurab Davitiani wrote:

Because once you determine that $_GET['option'] is *defined* then both of
these:

$_GET['option'] == '0'
$_GET['option'] == 0

will do exactly the same.

I'm replying to myself here, but I believe I made a mistake. These 2 are not
exactly the same since you'd still need to do an empty check in the second
case. Or strcomp.

Anyway, if you don't need to know about whether a GET variable is defined or
not, you don't need to use ==, you can just use strcomp. I think that's
what Chung Leong said, and I don't really disagree there.

[Zurab Davitiani]

Tim Streater wrote:

If option is undefined, then I would have thought that $_GET['option']
would also be undefined. If its undefined it cannot be equal to zero or
any other value, so why is the else clause not taken?

That's a big part of what this sub-thread was about. Because undefined value
is equal to 0/false/[empty string] with implicit type conversion. If you
need to know whether a variable is defined or not, use isset; and don't
turn off undefined notices to catch them. If it doesn't matter and you are
just comparing string values, use strcomp (or another way of string-only
comparison).

[Chung Leong]

"Zurab Davitiani" <ag*@mindless.c om> wrote in message
news:0n******** ********@newssv r27.news.prodig y.com...

Zurab Davitiani wrote:

Because once you determine that $_GET['option'] is *defined* then both of these:

$_GET['option'] == '0'
$_GET['option'] == 0

will do exactly the same.
I'm replying to myself here, but I believe I made a mistake. These 2 are

not exactly the same since you'd still need to do an empty check in the second
case. Or strcomp.

Anyway, if you don't need to know about whether a GET variable is defined or not, you don't need to use ==, you can just use strcomp. I think that's
what Chung Leong said, and I don't really disagree there.

I made somewhat of an mistake here too. Forgot that *any* non-numeric
string gets converted to 0 on numeric comparison. So the following is true:

if("Bobo the Clown" == 0) {
echo "Bobo is nothing!";
}

But the bottomline is that isset() doesn't help you here.

--
Obey the Clown - http://www.conradish.net/bobo/