Programming puzzles: processing lists!

[pier4r]

Thanks !

Yes arrays and matrices would be pretty powerful if, somehow, their processing would cost similarly to list (or having the same amount of helpful list commands. For example there is no sigma row or sigma array, while there is sigma list to get the sum of the numbers). Instead at times they are slow, especially with large matrices.

Or maybe I am influenced by past experiences. I didn't touch matrices for a while.