22
22. カテゴリ名の抽出
記事のカテゴリ名を(行単位ではなく名前で)抽出せよ.
22.hs
{-# LANGUAGE OverloadedStrings, DeriveGeneric #-} import Data.Aeson as A import Control.Applicative import System.IO.UTF8 as I8 import System.Environment import Data.Maybe import Data.ByteString.Lazy.UTF8 as B import GHC.Generics import Text.Regex.Posix import Prelude as P data Article = Article { text :: String, title :: String } deriving (Eq, Show, Generic) instance FromJSON Article main = do filename <- head <$> getArgs body <- fromString <$> I8.readFile filename I8.writeFile "22.txt" $ unlines $ map f2 $ filter f $ concatMap P.lines $ map (text . fromJust . A.decode) $ B.lines $ body where f = ((=~ ("^[[][[]:?(カテゴリ|Category):" :: String)) :: String -> Bool) f2 = tail . ((=~ (":[^]|]*" :: String)) :: String -> String)