io.read() not working - ComputerCraft Forums (archive)

Copilot #1

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7 posts

Posted 21 June 2013 - 12:24 AM

So in my program I'm using the command io.read(). I want it to read numbers, so from my research I found out that in order to do that I need to type in io.read("*number"), but whenever I use that command it spits out "Unsupported format". What's the solution to this? How the heck do I get a user to enter a number?

Lyqyd #2

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8543 posts

Posted 21 June 2013 - 12:55 AM

Split into new topic.

Don't use io.read(). Use plain ol' read() instead, and don't pass it any arguments. You can use tonumber() to convert the resulting string into a number. If the string cannot be converted into a number, tonumber() will return nil.

TheOddByte #3

1852 posts

Location Sweden

Posted 21 June 2013 - 08:22 AM

Example of what Lyqyd said


input = read()

if not tonumber(input) then
print("False")

else
print("True")
end

theoriginalbit #4

7508 posts

Location Australia

Posted 21 June 2013 - 08:33 AM

And a way to keep trying until you get a number


write("enter a number: ")
local input = read()
while not tonumber(input) do
  print("not a number")
  write("enter a number: ")
  input = read()
end

the above will keep asking for a number until they enter one, telling them when they don't


local input
repeat
  write("enter a number: ")
  input = read()
until tonumber(input)

the above will just keep asking until they enter a number, this method you cannot tell them they entered incorrectly

Copilot #5

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7 posts

Posted 22 June 2013 - 12:54 AM

Woo! Thanks all!

johnnic #6

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53 posts

Location Somewhere in ****** County, *******

Posted 23 June 2013 - 12:13 AM

io.read() can only print what was written. read() can be used as read(var number or "string").

theoriginalbit #7

7508 posts

Location Australia

Posted 23 June 2013 - 03:47 AM

johnnic, on 23 June 2013 - 12:13 AM said:
io.read() can only print what was written. read() can be used as read(var number or "string").

Not quite, io.read() does take input from the user, and will return the string of the input, just like read. the standard read can only return a string.