CODEWITHSUNDEEP
haskellmonads
asbxl
asbxl

Reputation: 123

Convert [IO Int] to IO [Int] in Haskell?

I have this code that fits my need:

f :: [IO Int] -> IO [Int]
f [] = return []
f (x:xs) = do 
  a <- x
  as <- f xs
  return (a:as)

But I thougth there would be a predefined way (msum ?)

But I can't see how.

Any help would be welcome. Thx

Upvotes: 5

Views: 583

Answers (1)

Mikhail Glushenkov
Mikhail Glushenkov

Reputation: 15078

Yes, it's available in the standard library under the name sequence. It has a more general type than your f: Monad m => [m a] -> m [a], since it works for any Monad, not just IO.

You could find it yourself by searching for type [IO a] -> IO [a] on Hoogle.

Upvotes: 21

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