$s = "23,452,789 views";;
$s =~ m[((?:\d+,)?(?:\d+,)?\d+) views] and ( $n = $1 ) =~ s[,][]g and print $n;;
23452789

$s = "452,789 views";;
$s =~ m[((?:\d+,)?(?:\d+,)?\d+) views] and ( $n = $1 ) =~ s[,][]g and print $n;;
452789

$s = "789 views";;
$s =~ m[((?:\d+,)?(?:\d+,)?\d+) views] and ( $n = $1 ) =~ s[,][]g and print $n;;
789