I keep getting a match type error. I've changed the syntax but cant seem to figure out the error

I'm trying to solve https://www.codewars.com/kata/560a4962c0cc5c2a16000068/train/haskell

eqSumPowDig :: Int -> Int -> [Int]
eqSumPowDig hmax po = [x | x<-[2..hmax], expo (show x) po]
                                              where expo :: String -> Int -> Bool
                                                    expo b e = sum [(read n)^e | n<-b] == b

I get the error

    • Couldn't match type ‘Char’ with ‘[Char]’
      Expected type: String
        Actual type: Char
    • In the first argument of ‘read’, namely ‘n’
      In the expression: (read n)
      In the first argument of ‘sum’, namely ‘[(read n) | n <- b]’
  |
6 |                                                     expo b e = (sum [(read n) | n<-b]) == b
  |                                                                            ^

CodePudding user response：

Because expo :: String -> Int -> Bool b is a String. Then in the list comprehension [… | n<-b] n becomes an element of b which is a Char. But read expects a String