undefined index shows in my debuging mode [duplicate]

PHP Notice: Undefined index: in /home/lankade792/public_html/wp-content/themes/adifier/functions.php on line 675

$list = array();
$loaded_fonts = array();
foreach( $load_fonts as $key => $data ){
    if( !empty( $data['font'] ) && !isset( $loaded_fonts[$data['font']] ) ){
        $loaded_fonts[$data['font']] = $data['weight'];
    }
    else{
        $loaded_fonts[$data['font']] .= ','.$data['weight'];
    }
}

PHP Notice: Undefined index: Rs in /home/lankade792/public_html/wp-content/plugins/adifier-system/functions.php on line 657

array(
            'font'     => adifier_get_option( 'text_font' ),
            'weight'   => adifier_get_option( 'text_font_weight' ).',600,700',
        ),
        array(
            'font'     => adifier_get_option( 'title_font' ),
            'weight'   => adifier_get_option( 'title_font_weight' ).',400,500',
        ),