Haskell : Error in split function -


i new @ haskell. want implement split function, splites list 2 parts:

split 2 [1,2,3] → ([1,2], [3]) --means first part has length 2, second - length x-2 split 2 [1] → ([1], [])   split :: int -> [a] -> ([a],[a]) split 0 x = ([], x) split n x = splith n x []  splith :: int -> [a] -> [a] -> ([a], [a]) splith n (x:xs) begin | n == 0 = (begin, xs)                       | otherwise = splith n-1 xs (x:begin) -- here error      main = print(split 2 [1,2,3] )

but code not compile. error

`couldn't match expected type ‘([a], [a])’             actual type ‘[a0] -> [a0] -> ([a0], [a0])’ relevant bindings include   begin :: [a] (bound @ jdoodle.hs:6:17)   xs :: [a] (bound @ jdoodle.hs:6:13)   x :: (bound @ jdoodle.hs:6:11)   splith :: int -> [a] -> [a] -> ([a], [a]) (bound @ jdoodle.hs:6:1) probable cause: ‘splith’ applied few arguments in first argument of ‘(-)’, namely ‘splith n’ in expression: splith n - 1 xs (x : begin)`

what cause error ?

put parentheses around expression n-1:

splith (n-1) xs (x:begin)

look @ section 7, "function application has precedence on operators" of this article explanation:

so if see this:

f b c + g d e

you know adding result of 2 function calls rather calling 1 function 1 of arguments being sum of 2 terms.


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