将其从字符串转换为 int 列表值后如何求和？

Question

I have basic problem with Haskell but I'm pretty new that's way struggled extremely already I have got limited knowledge related haskell (before this I did deal with C root with languages) so far I explaıned myself

Imagine that we have such that list on String format in haskell ["2","76","564"] so I desire to convert Integer [2,76,564] something like that.(I did )

after I need to sum of all list element

2+76+564 = 642 stopped in this part

convert::  [String] -> [Int]
convert = map read
convert (xs:x)= x + convert xs

How can I calculate after that I convert part.

Answer 1

Your convert does not makes much sense: it has two clauses where the first clause has no parameter and the second one has one parameter. It is sufficient to implement convert as:

convert :: [String] -> [Int]
convert = map read

You can then calculate the sum with sum:: (Foldable f, Num a) => fa -> a :

convertSum :: [String] -> Int
convertSum = sum . convert

We can also implement convertSum with recursion in that case it looks like:

convertSum :: [String] -> Int
convertSum [] = …
convertSum (x:xs) = read x + …

where I leave implementing the … parts as an exercise.