How to make setters in 2D Array Haskell

Question

I currently have a 2D array declared as:

import Data.Array.Unboxed
listArray ((0,0), (9,9)) (replicate 100 \'f\') ∷  UArray (Int, Int) Char

I a

Answer 1

The simplest update function for arrays is (//), which has this type:

(//) :: (IArray a e, Ix i) => a i e -> [(i, e)] -> a i e 

For example:

Data.Array.Unboxed> listArray (0, 4) "abcde" // [(1, 'f')] :: UArray Int Char
array (0,4) [(0,'a'),(1,'f'),(2,'c'),(3,'d'),(4,'e')]

You can access particular elements with (!):

Data.Array.Unboxed> it ! 1
'f'