[Haskell-cafe] Nested Lists

Hi all, If I have a list, and I'd like to convert it to a list of lists, each of length n, I can use a function like bunch: bunch _ [] = [] bunch n as = let (c,cs) = splitAt n as in c:bunch n cs bunch 8 [1..16] [[1,2,3,4,5,6,7,8],[9,10,11,12,13,14,15,16]] If I now want to do the same for the

Re: [Haskell-cafe] Nested Lists

Hi Paul, I don't have time to solve your actual problem, but I think it's doable using associated type families. I attach a module which I'm using in my current project that does things quite similar to what you're asking for. For example: *Main replicateArray (3 : IntArr) 4 [4,4,4]

Re: [Haskell-cafe] Nested Lists

How about... *Main bunch () [1..16] [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16] *Main bunch (8 :+: ()) [1..16] [[1,2,3,4,5,6,7,8],[9,10,11,12,13,14,15,16]] *Main bunch (8 :+: 4 :+: ()) [1..16] [[[1,2,3,4],[5,6,7,8]],[[9,10,11,12],[13,14,15,16]]] *Main bunch (8 :+: 4 :+: 2 :+: ()) [1..16]

Re: [Haskell-cafe] Nested Lists

On Thu, 4 Jun 2009, Paul Keir wrote: Hi all, If I have a list, and I'd like to convert it to a list of lists, each of length n, I can use a function like bunch: bunch _ [] = [] bunch n as = let (c,cs) = splitAt n as in c:bunch n cs

[Haskell-cafe] Nested Lists

You can also try this: bunch n f = takeWhile (not . null) . unfoldr (Just . (f *** id) . splitAt n) (bunch 8 . bunch 4 . bunch 2) id [1..16] Any way, it's not possible to take list [8, 4, 2], because it's length need to be known at compile time.