Notice: Undefined Index in Xampp. How do I fix this?

Question

Before you ask, yes I have searched through nearly 20 different "undefined index" questions on SO before asking this question. Sadly none of them managed to even give me a clue to fixing the problem. I have a simple index.php file that switches through different html files depending on what link you press. On a live server that seems to be no problem at all but when I use Xampp, I receive a long list of "undefined indexes" and I can't figure out why. My Index.php file below. The undefined index message states that "Undefined Index rv in each line."

<?php
include ("anime_header.html");

if($_GET['rv'] == "amnesia")         include ("Amnesia.html");
else if($_GET['rv'] == "shingeki")   include ("AttackOnTitan.html");
else if($_GET['rv'] == "chuunibyou") include ("Chuunibyou.html");
else if($_GET['rv'] == "crimeedge")  include ("CrimeEdge.html");
else if($_GET['rv'] == "datealive")  include ("DateALive.html");
else if($_GET['rv'] == "duskmaiden") include ("DuskMaiden.html");
else if($_GET['rv'] == "gargantia")  include ("Gargantia.html");
else if($_GET['rv'] == "K_anime")    include ("K_Anime.html");
else if($_GET['rv'] == "karneval")   include ("Karneval.html");
else if($_GET['rv'] == "kotoura")    include ("Kotoura-San.html");
else if($_GET['rv'] == "kaibutsu")   include ("LittleMonster.html");
else if($_GET['rv'] == "nerawareta") include ("Nerewareta.html");
else if($_GET['rv'] == "redgarden")  include ("RedGarden.html");
else if($_GET['rv'] == "saikano")    include ("Saikano.html");
else if($_GET['rv'] == "sakurasou")  include ("Sakurasou.html");
else if($_GET['rv'] == "sasamisan")  include ("Sasami-San.html");
else if($_GET['rv'] == "vividred")   include ("Vividred.html");
else include ("animereviews.html");

include ("ReviewFooter.html");
?>

I'm not looking for a way to suppress the error message but an understanding as to why it appears in on my Xampp server only and how to fix it in the future.

possible duplicate of [PHP: "Notice: Undefined variable" and "Notice: Undefined index"](http://stackoverflow.com/questions/4261133/php-notice-undefined-variable-and-notice-undefined-index) — mario, Sep 03 '13 at 00:42
Copy the input to a temporary variable *once*, then compare. Preferrably use a `switch` or array map instead. — mario, Sep 03 '13 at 00:43
The message is clear enough: the variable $_GET['rv'] is not set. As to why that is, you'd have to look at the method you're using to link to this page and make sure you have `rv=something` in the query string. — , Sep 03 '13 at 00:43
`On a live server that seems to be no problem` That's because on the live server, you have warnings disabled. If you turn on error_reporting, you should again see the errors you see, just like on XAMPP. — Dave Chen, Sep 03 '13 at 00:59
The notice should have a file name and a line number in it. Use that information to narrow down the problem. — Sverri M. Olsen, Sep 03 '13 at 01:02
Try running [`error_reporting(0)`](http://php.net/manual/en/function.error-reporting.php) on your XAMPP. You should no longer see the warnings. — Dave Chen, Sep 03 '13 at 01:02
possible duplicate of [how to remove warning messages in php?](http://stackoverflow.com/questions/1987579/how-to-remove-warning-messages-in-php) — Dave Chen, Sep 03 '13 at 01:05
@SverriM.Olsen Every line in which 'rv' is present contains the error. — Arthur Hargrave, Sep 03 '13 at 01:10
@ArthurHargrave I know. By using the file name and line number, and the notice's message ("Undefined index"), it should be obvious what is wrong: The index `'rv'` is undefined on every single line. In other words, you need to make sure that it is set using `isset()`. — Sverri M. Olsen, Sep 03 '13 at 01:14

score 0 · Answer 1 · answered Sep 03 '13 at 01:28

That error appears when you try to access a non-existing key in an array. As an example, let's make a simple array:

$myarr = array(
    'a' => 5
);

If you try to access the "a" key, it will run without any errors:

if ($myarr['a'] == 5){
    echo 'Perfect!';
}

However, if you try to access a key that has not been set, a "Undefined Index" error will occur:

if ($myarr['b'] == 6){
    echo 'The previous line should cause an error.';
}

In order to fix this, ensure that the "rv" key exists before accessing it. The most commonly used function to ensure that a key is set is isset:

if(!isset($_GET['rv'])){
    echo 'Oops, it seems like that key is not set!';
    exit;
}

score 0 · Answer 2 · answered Sep 03 '13 at 05:32

Check if $_GET['rv'] is set

<?php
$rv = $_GET['rv'];
if(isset($rv)){
    include ("anime_header.html");

    if($rv == "amnesia")         include ("Amnesia.html");
    else if($rv == "shingeki")   include ("AttackOnTitan.html");
    else if($rv == "chuunibyou") include ("Chuunibyou.html");
    else if($rv == "crimeedge")  include ("CrimeEdge.html");
    else if($rv == "datealive")  include ("DateALive.html");
    else if($rv == "duskmaiden") include ("DuskMaiden.html");
    else if($rv == "gargantia")  include ("Gargantia.html");
    else if($rv == "K_anime")    include ("K_Anime.html");
    else if($rv == "karneval")   include ("Karneval.html");
    else if($rv == "kotoura")    include ("Kotoura-San.html");
    else if($rv == "kaibutsu")   include ("LittleMonster.html");
    else if($rv == "nerawareta") include ("Nerewareta.html");
    else if($rv == "redgarden")  include ("RedGarden.html");
    else if($rv == "saikano")    include ("Saikano.html");
    else if($rv == "sakurasou")  include ("Sakurasou.html");
    else if($rv == "sasamisan")  include ("Sasami-San.html");
    else if($rv == "vividred")   include ("Vividred.html");
    else include ("animereviews.html");

    include ("ReviewFooter.html");
}
?>

Notice: Undefined Index in Xampp. How do I fix this?

2 Answers2