Re: [Haskell-cafe] How to devide matrix into small blocks

On Wed, 13 Jun 2007, L.Guo wrote:

I already have one matrix of type [[a]] to store one image.

What I want to do is to devide the image into severial small blocks in same size.

To do that, I wrote this tool function.

chop :: Int -> [a] -> [[a]] chop _ [] = [] chop n ls = take n ls : chop n (drop n ls)

I assume that it is more efficient to use 'splitAt' instead of 'take' and 'drop'.

But I do not know how to use it to write the function.

chop blockHeight (map (chop blockWidth) image)