Input line of numbers in haskell and convert to list

Question

Basically what is said in the title.

I would like to input

4 6 17 4

and it would give me the list

[4, 6, 17, 4]

ErikR · Accepted Answer · 2014-12-06 22:07:39Z

3

main = do
  ln <- getLine
  let ints = map read (words ln)  :: [Int]
  ... do something with ints...

ints is a list of Int values.

The type signature :: [Int] is needed so read knows what to return.

answered Dec 6, 2014 at 22:07

ErikR

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4 Comments

Greg Peckory Over a year ago

Couldn't match type [] with IO Expected type: IO Int Actual type: [Int] …

David Young Over a year ago

@JohnDoe The code in this answer doesn't cause that error, so it must be in a different part. Which expression does the error message say has the error?

Greg Peckory Over a year ago

I just attempted to output the set "ints". And I get this error. I don't understand, I did it as I normally would in the console

Greg Peckory Over a year ago

How do I output set to console and not string?

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