On 2018-01-15 16:02, trent shipley wrote:
My "intuitive" way of doing this is to use recursion. Take the list, Find the first list element. Send the rest of the list back to the function to keep building the list of positions. Until you are out of list, then you halt.
Sounds like a sensible plan to me!
I have zero intuition on how to do that on a list comprehension, and the tuple pairs you get from zip just makes it harder.
Do you really need to do it using a list comprehension? As far as I can see, the only requirement is that you use the 'find' function.
I don't really want a solution. What I really want to know is whether there is a "find" function I can import, how to import it, and some relevant documentation.
Yes, there is a standard 'find' function in the Data.List module. See here: http://hackage.haskell.org/package/base-4.10.1.0/docs/Data-List.html#v:find It is part of the 'base' package, i.e. you most certainly already have it. You can import it by using e.g. -- Bring everything in Data.List into scope import Data.List -- Bring just the 'find' function into scope import Data.List (find) -- Frerich Raabe - raabe@froglogic.com www.froglogic.com - Multi-Platform GUI Testing