Unique characters: Difference between revisions

[ "133252abcdeeffd",

"a6789798st",

"yxcdfgxcyz"

]</lang>

{{Out}}

<pre>156bgstz</pre>

Or folding the strings down to a hash of character frequencies:

<lang haskell>import qualified Data.Map.Strict as M

--------- UNIQUE CHARACTERS FROM A LIST OF STRINGS -------

uniqueChars :: [String] -> String

uniqueChars ks =

[ k

| (k, v) <-

M.assocs $

foldr

(flip (foldr (flip (M.insertWith (+)) 1)))

M.empty

ks,

1 == v

]

--------------------------- TEST -------------------------

main :: IO ()

main =

putStrLn $

uniqueChars