Undefined offset: 1 in C:\xampp\htdocs\xx\index.php on line 8

Maaf sebelumnya saya anak sma mencoba buat project dgn php, tapi ada kendala muncul seperti Undefined offset: 1 in C:\xampp\htdocs\ig2\index.php on line 8

$hari = date("F j, Y, g:i a");
$right = file_get_contents("xxx");
$cop = explode('p3">' , $right);
$cop1 = explode('</a>' , $cop[1] );
$cop2 = $cop1[0];
$ck = preg_replace('/\s+/', '', $cop2);

mohon bantuannya, terimakasih