Getting variables and some other stuff from text file

I know for a fact that computercraft can create and write to files, but I don't know how to retrieve informations from that file, such as coordinates for turtles, block, etc..

Can you help me please ?

if the file with the coords is like this :
x = 1
y = 2
z = 3
then open the file then use a for loop to add each line to a table which will then let you cut out the first 4 characters and leave you with the number of each line or example

nLines = (numberOfLines)
tLines = {} -- table of lines
variable = fs.open("filename", "r") --(you can use io.open aswel but i prefer the fs api)
for i = 1,nLines do -- loops for nLines times
variable2 = variable.read() -- reads the line
if variable2 ~= "" or nil then -- checks if the line is blank or non-existent
variable3 = string.sub(variable2, 5,5) -- cuts out the x = or y = and so on...
table.insert(tLines, variable3) -- inserts the modified line into the table
end
end

i think this should work but it is untested so there might be errors…

better idea, use a table to store the co-ordinates, so:

mycoords={}
mycoords[1]={['x']=20,['y']=25}
mycoords[2]={['x']=,10['y']=30}

then to store it you simply write the output of textutils.serialize(mycoords) to a file, to get all your data back use

mycoords=textutils.unserialize(io.open('yourfilename','r'):readall)

I think the best way of going about this would be to store variables as awsumben said, while reading and interpreting them using string.gmatch instead of string.sub.

file = fs.open('your/file/path','r')

local data = file.readAll()

for index,value in data:gmatch('([%w_])%s-=%s-(%d)') do
  print(index, value)
end

in this case, it'd output
x1
y2
z3

You could also store them as a lua-formatted table of variables as KaoS said, and load them using loadfile() and pcall() so that the program doesn't crash.

--  the file:
return {
  x = 1;
  y = 2;
  z = 3;
}

-- the file loader
local vars = pcall(loadfile('your/file/path'))

However I'm not even sure if loadstring and loadfile are both available, haha.

Anover question How can I create a file ? (yes, I think it's a sutpid question but i don't know how to create one.)

Pretty sure you can just use fs.write() to a file location that doesn't exist yet.

thanks

use this to create a file:
k = fs.open("filename", "w")
k.close()
this will also reset a file that exists