Re: Replace the last item in a string of 'words'

[Paul K <paul@...>]

Hi Russ,

> 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 5 -29501 0 V6

Why not `:gsub("%S+$", "newval")`?

Paul.

On Wed, Jun 26, 2019 at 10:45 AM Russell Haley <russ.haley@gmail.com> wrote:
>
> 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