I have a file that I want to read only a few lines, not all lines. I get by GET the lines I want to read, which are numbers. I can only read the entire file.
local inicio = GET["inicio"]
local fim = GET["fim"]
local f = io.open(ficheiro, "r" ) --ler ficheiro
for line in f:lines() do --correr lignas
--insert table
table.insert(dat_array, line)
end
For example if the beginning is 2 and the end 6, read in the cycle is only those lines.
A way:
local l=0
for line in f:lines() do
l=l+1
if l>=inicio and l<=fim then
table.insert(dat_array, line)
end
if l>=fim then break end
end
f:close()
Another way:
for l=1,inicio-1 do
f:read()
end
for l=inicio,fim do
table.insert(dat_array, f:read())
end
f:close()
The first way works even if the file has fewer rows than the given range. In this case, you have to adapt the second way to stop the process if f:read() returns nil (which is a good idea anyway).