数字の文字列をread使って数字列に変換する - Qiita

Prelude> let n = "123456789" :: String Prelude> n "123456789" Prelude> map return n :: [String] ["1","2","3","4","5","6","7","8","9"] Prelude> map (read . return) n :: [Int] [1,2,3,4,5,6,7,8,9] Prelude> map (read . return) n :: [Float] [1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0] Prelude> let parse str = map (read . return) str :: [Int] Prelude> :t parse parse :: [Char] -> [Int] Prelude> map parse ["1234

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