http://qs321.pair.com?node_id=1220374


in reply to use warnings is complaining

Well, like your warning is telling you, " " is not a number.

So quite simply you need to either make it a number, or not require it to be a number.

You might do this by testing whether the value is all whitespace, and set it to "-" x 10 or sprintf '%10.2f' based on that test. Then when printing the blended values, use %10s.