Replace the last item in a string of 'words'

[Russell Haley <russ.haley@...>]

Hi,

Given a file of lines in a file like below, what would be the best way to replace the last item on each line (e.g. V6 in the last line)?

twa01.dat 16 2000 16 0 12 10980 0 I
twa01.dat 16 2000 16 0 14 -9048 0 II
twa01.dat 16 2000 16 0 1 -25727 0 III
twa01.dat 16 2000 16 0 -14 29120 0 aVR
twa01.dat 16 2000 16 0 5 15064 0 aVL
twa01.dat 16 2000 16 0 8 17036 0 aVF
twa01.dat 16 2000 16 0 2 19694 0 V1
twa01.dat 16 2000 16 0 12 26289 0 V2
twa01.dat 16 2000 16 0 21 -23938 0 V3
twa01.dat 16 2000 16 0 18 11347 0 V4
twa01.dat 16 2000 16 0 6 27591 0 V5
twa01.dat 16 2000 16 0 5 -29501 0 V6

I'm not even having much luck with simply capturing the separate items. I've tried a bunch of variations on this:

for line in io.lines(file_name) do
    if line:match('.dat') then
        local t = {}
        for v in line:gmatch('%s(.)') do
            t[#t+1] = v
        end
        for i,v in pairs(t) do
            print(i,v)
        end
    end
end

Any advice would be appreciated.

Thanks!

Russ