Re: Using Lua to combine CSV files

[Shmuel Zeigerman <shmuz@...>]

The following is a straightforward solution (not optimized for
performance).

local timestamp1, timestamp2, first, last, outlogfile = ...
timestamp1, timestamp2 = tonumber(timestamp1), tonumber(timestamp2)
local fout = assert (io.open (outlogfile, "w"))
local done
for i = first, last do
  if done then break end
  local filename = "logfile" .. i .. ".csv"
  for line in io.lines(filename) do
    local timestamp = tonumber (line:match ("^[^,]+"))
    if timestamp then
      if timestamp >= timestamp1 then
        if timestamp <= timestamp2 then fout:write (line, "\n")
        else done = true break
        end
      end
    else
      error ("record with bad timestamp in file " .. filename)
    end
  end
end
fout:close()

--
Shmuel