$s = 'a1 1 2 1.0 1.1 1.2 1.3';;
print grep defined, $s =~ m[([a-z]\d)\s+(\d)\s+(\d)(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?];;
a1 1 2 1.0 1.1 1.2 1.3

$s = 'a1 1 2 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7';;
print grep defined, $s =~ m[([a-z]\d)\s+(\d)\s+(\d)(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?(?:\s+(\d\.\d))?];;
a1 1 2 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7