php通知未定义索引会话[重复]

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Cannot access the session array with php 3 answers

i have PHP Notice: Undefined index: langid in the error logs and here is the code it's defined so any idea about what is wrong with my code

<?php 

if(($_SESSION['langid'])!="" ){

    $langid=$_SESSION['langid'];
    $_SESSION['langid']=$langid;


    if(isset($_REQUEST['langid']) && $_REQUEST['langid']!="" ){
        $langid=$_REQUEST['langid'];
        $_SESSION['langid']=$langid;
    }else{

    }

}else{
$langid=1;
$_SESSION['langid']=$langid;



if(isset($_REQUEST['langid']) && $_REQUEST['langid']!="" ){
    $langid=$_REQUEST['langid'];
    $_SESSION['langid']=$langid;
}else{

}
}

</div>

Try :

<?php

if ( isset($_SESSION['langid']) )
{

    $langid=$_SESSION['langid'];
    $_SESSION['langid']=$langid;


    if(isset($_REQUEST['langid']) && $_REQUEST['langid']!="" ){
        $langid=$_REQUEST['langid'];
        $_SESSION['langid']=$langid;
    }else{

    }

}else{
$langid=1;
$_SESSION['langid']=$langid;



if(isset($_REQUEST['langid']) && $_REQUEST['langid']!="" ){
    $langid=$_REQUEST['langid'];
    $_SESSION['langid']=$langid;
}else{

}
}

?>

And you will will have no notices about warnings .but the code is no sense :

$langid=$_SESSION['langid'];
$_SESSION['langid']=$langid;

has no sense