Need help with a while-loop of mine.

Hello. I'm trying to create a while loop where the user must input a number into the computer, and check it for validation. My problem is, I can't figure out how to make it so that the input MUST be a number. Specifically, I want it to be a seven digit number. I have no problems when the input must be one of a few specific words, but I don't know how to set it so that the entry must be a number. Here's a segment of my code:


print("To Proceed, Please Validate Your Identity:")
print("")
while true do
write("Personal Identification Number: ")
id = read()
if id == ??? a 7 digit number ??? then
break
else
print("Invalid Entry")
print("Your ID# Must Be A 7 Digit Number")
sleep(2)
term.setCursorPos(1,5)
term.clearLine()
term.setCursorPos(1,4)
term.clearLine()
term.setCursorPos(1,3)
term.clearLine()
end
end


I don't care what number the user inputs, so long as it is seven digits long. I'd really appreciate any assistance :P/>/>

if tonumber(thestringyouread) == false then
print("The string you entered couldn't be recognized as a number, please try again.")
end

might work, will have to have a pro confirm this but I tihnk this should be right.

You could check the length of the string for your number of digits, then tonumber() it and check that the return is not nil

tonumber returns nil if it's not passes a number, not false. So..

if string.len(id)==7 and tonumber(id)~=nil then
  --code to run if it's good
else
  --code if it's bad

Thanks guys! I managed to make something work. Appreciate the help!

why tonumber through? just use if type(var)=='number' then