Fill in missing numbers in range

I need to edit a list of numbers on the following form:

1 1.0
2 1.4
5 2.1
7 1.9

I want:
1 1.0
2 1.4
3 0.0
4 0.0
5 2.1
6 0.0
7 1.9

(i want to add the missing number in column 1 together with 0.0 in column 2).

I guess it is rather trivial but i didn't even manage to read column 1 and column 2 into separate variables (except from in awk, but it didn't help me much...).

Any ideas how to get started?
Thanks,
Howie

Could you be more clear in what you are trying to achieve. Are you reading from one file and trying to generate a list of new nos based on certain conditions or you have 2 files and are you trying to merge it???Or do you want to just read the file1 into variables??

Sorry.

I read the list from one file, and want to write to a new file. The only condition is that i want to have "complete" listing, with a complete range from the lowest number to the highest number, which in this case is from 1-7.

Thanks for your response!

awk 'BEGIN{lno=1} {while(lno != $1) {print lno,"0.0";lno++;}} {print; lno++;}' filename

Thank You very much! It works perfect!

A bit over the top for me, but i'll try and figure out how it works. Hopefully i will learn something.

Thanks again,
Howie

Can any body put code for the same with "sed"?