Attempt to call nil

Right! I am brand new to lua coding, I understand very little.

I am having an issue with a bit of code I was messing around with

x = rs.getAnalogInput("left")

I have written it exactly as the wiki wrote it, but I am getting the error "Attempt to call nil"

Is it because I am assigning it to a variable? Or am I doing something else wrong I don't understand..

Please be patient, I am new to this :)/>

What version of ComputerCraft are you running?

Which CC/MC version are you using? For this function you must use CC 1.51 or above and Minecraft 1.5 or above.
EDIT: Half ninja'd

Ahh I should have posted that in my OP, Apologies.. I am still using FTB ultimate on 1.4.7! Thanks for the help, guys

I'll update the wiki.

EDIT: Done.

Elgriton, on 09 May 2013 - 02:28 AM said:

Ahh I should have posted that in my OP, Apologies.. I am still using FTB ultimate on 1.4.7! Thanks for the help, guys

NP, bro. Any time.

While this thread is still slightly relevant, is there a way to detect the signal of the redstone signal without using that code? I had some neat ideas to use with this

rs.getInput( [side] )

where [side] is the side that the redstone is on.

EDIT: Here are some usage examples:
One off check to create a branch in code

if rs.getInput('left') then
  print('There is a redstone signal on the left')
else
  print('There is no redstone signal on the left')
end

Remember the state, but also print some stuff

local leftState = rs.getInput('left')
print('The redstone input on the left is '..(leftState and 'on.' or 'off.'))

Loop through all the sides and print the state

for _,side in pairs(rs.getSides()) do
  print('The redstone input on the '..side..' is '..(rs.getInput(side) and 'on.' or 'off.'))
end

theoriginalbit, on 09 May 2013 - 02:38 AM said:

rs.getInput( [side] )

where [side] is the side that the redstone is on.

Sorry I should say, read the strength of the signal! I know this code makes it possible, I am just wondering if it is possible without it. hmm

Elgriton, on 09 May 2013 - 02:40 AM said:

Sorry I should say, read the strength of the signal! I know this code makes it possible, I am just wondering if it is possible without it. hmm

Nope, sorry but this is not possible using that version of CC :(/>

No worries! Thanks for the help! I'm sure you will see me around more while this noob learns lua ;)/> just hope ya put up with me

Elgriton, on 09 May 2013 - 02:40 AM said:

Sorry I should say, read the strength of the signal! I know this code makes it possible, I am just wondering if it is possible without it. hmm

The "redstone update" came out in Minecraft 1.5, so there was no way to get strength in 1.4.7

Elgriton, on 09 May 2013 - 02:44 AM said:

while this noob learns lua

Check out the PIL http://www.lua.org/pil/1.html
And obviously the ComputerCraft wiki http://computercraft.info/wiki/index.php?title=Category:APIs
The 'Tutorials' section of these forums are quite handy sometimes.
And Google is your friend!