Assigning Values to an Array: Difference between revisions

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===Mutable Array===

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import Data.Array.MArray

import Data.Array.IO

main = do -- Create the array of data with all elements intialized to 3

a <- newArray (0, 4) 3 :: IO (IOArray Int Int)

-- Print entry

readArray a 2 >>= print -- prints "3"

-- Update one entry

writeArray a 2 5

-- Print entry again

readArray a 2 >>= print -- prints "5"