How to solve php Notice: Undefined index

How to solve php Notice: Undefined index

I am working on a php project which is already been developed. Now my work is to change some css files. So to do this I just downloaded all the files from the server along with the database. After all the setup I am getting an error when I am browsing the page is

Notice: Undefined index: lang_selected in language.php on line 38  

and the piece of code which is doing this stuff is

if((!isset($_GET['q'])) && ($_SESSION['lang_selected'] == "") && ($ln == 1))    {        $language = $setshow['es_lang'];       if($language=="France")      $lan="french";        else if($language=="Croatian")      $lan="croatian";        else if($language=="Dutch")      $lan="dutch";        else if($language=="German")      $lan="german";        else if($language=="Greek")      $lan="greek";        else if($language=="Italian")      $lan="italian";        else if($language=="Indonesian")      $lan="indonesian";        else if($language=="Russia")      $lan="russian";        else if($language=="Spain")      $lan="spanish";        else if($language=="Usa")      $lan="english_v1";        else if($language=="China")      $lan="chinese";        else if($language=="Japanese")      $lan="japanese";        else if($language=="Korea")      $lan="korean";        else if($language=="Saudia")      $lan="arabic";        else if($language=="Norwegian")      $lan="norwegian";        else if($language=="Malaysian")      $lan="malaysian";        else if($language=="Persian")      $lan="persian";        else if($language=="Portuguese")      $lan="portuguese";        else if($language=="Serbain")      $lan="serbain";        else if($language=="Swedish")      $lan="swedish";        else if($language=="Thai")      $lan="thai";        else if($language=="Vietnamese")      $lan="vietnamese";        else if($language=="Turkey")      $lan="turkish";        unset($_SESSION['lang']);     $_SESSION['lang']=$lan;     $_SESSION['language']=$language;      }  

So can some one kindly tell me why this piece of error is coming and how to solve this issue? Any help and suggestions will be appreciable. Thanks

Answer by j0k for How to solve php Notice: Undefined index

You should test if $_SESSION['lang_selected'] exists first.

if(!isset($_GET['q']) && (isset($_SESSION['lang_selected']) && $_SESSION['lang_selected'] == "") && ($ln == 1))  

Answer by Gung Foo for How to solve php Notice: Undefined index

To test if an array index exists without triggering a notice use isset().

if(isset($array['index'])) doSomething();  

Answer by shannonman for How to solve php Notice: Undefined index

Check to see if $_SESSION['lang_selected'] is set using

if(isset($_SESSION['lang_selected'])) {      //do something when lang_selected contains a value  }  

Answer by Dharmendra for How to solve php Notice: Undefined index

there is problem with $_SESSION['lang_selected'] , I think it is not set.

Answer by Krunal Goswami for How to solve php Notice: Undefined index

use @$_SESSION['lang_selected'] temporary solution,

Fatal error: Call to a member function getElementsByTagName() on a non-object in D:\XAMPP INSTALLASTION\xampp\htdocs\endunpratama9i\www-stackoverflow-info-proses.php on line 72