Programming Fundamentals/Files/Lua
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files.lua
[edit | edit source]-- This program creates a file, adds data to the file, displays the file,
-- appends more data to the file, displays the file, and then deletes the file.
-- It will not run if the file already exists.
--
-- References:
-- https://www.mathsisfun.com/temperature-conversion.html
-- https://www.lua.org/manual/5.1/manual.html
function create_file(filename)
local file
file = io.open(filename, "w")
file:write("C\tF\n")
for c = 0, 50, 1 do
f = c * 9 / 5 + 32
file:write(c .. "\t" .. f .. "\n")
end
file:close()
end
function read_file(filename)
local file
local line
file = io.open(filename, "r")
while true do
line = file:read()
if line == nil then
break
end
io.write(line, "\n")
end
file:close()
io.write("\n")
end
function append_file(filename)
local file = io.open(filename, "a")
for c = 51, 100, 1 do
f = c * 9 / 5 + 32
file:write(c .. "\t" .. f .. "\n")
end
file:close()
end
function delete_file(filename)
os.remove(filename)
end
function file_exists(filename)
local file
file = io.open(filename, "r")
if file ~= nil then
file:close()
return true
else
return false
end
end
function main()
local filename = "~file.txt"
if file_exists(filename) then
io.write("File already exists.")
else
create_file(filename)
read_file(filename)
append_file(filename)
read_file(filename)
delete_file(filename)
end
end
main()
Try It
[edit | edit source]Copy and paste the code above into one of the following free online development environments or use your own Lua compiler / interpreter / IDE.