Remove characters from String in Haskell -


i creating program reads text file , splits words , stores them in list. have been trying create function takes in string whole text string file , remove punctuation e.g. ";", ",", "." unfortunately haven't had luck yet. program works without punctuation function, not when include (towords filecontents) please can @ have done , see doing wrong.

here code have far:

main =          contents <- readfile "largetextfile.txt"        let lowcontents = map tolower contents        let outstr = countwords (lowcontents)        let finalstr = sortoccurrences (outstr)        let reversedstr = reverse finalstr        putstrln "word | occurrence "        mapm_ (printlist) reversedstr  -- counts words. countwords :: string -> [(string, int)] countwords filecontents = countoccurrences (towords (removepunc filecontents))  -- splits words , removes linking words. towords :: string -> [string] towords s = filter (\w -> w `notelem` ["an","the","for"]) (words s)  -- remove punctuation text string. removepunc :: string -> string removepunc xs = x | x <- xs, not (x `elem` ",.?!-:;\"\'")  -- counts, how each string in given list appears. countoccurrences :: [string] -> [(string, int)] countoccurrences xs = map (\xs -> (head xs, length xs)) . group . sort $ xs  -- sort list in order of occurrences. sortoccurrences :: [(string, int)] -> [(string, int)] sortoccurrences sort = sortby (comparing snd) sort  -- prints list in format. printlist = putstrln((fst a) ++ " | " ++ (show $ snd a))

you want:

removepunc xs = [ x | x <- xs, not (x `elem` ",.?!-:;\"\'") ]

with brackets.


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