Haskell - Capitalize all letters in a list [String] with toUpper

Question

I have a list [String] the task ist to remove those elements in the list, which have \"q\" or \"p\" and then capitalize all letters in the list with toUpper.

What I

Answer 1

You're almost there, you just need a second map.

map (map toUpper) (filter (\x -> not('p' `elem` x || 'q' `elem` x)) myList)

This is because String is completely synonymous with [Char] in vanilla haskell. Since the type of map is

(a->b) -> [a] -> b

and we have

toUpper :: Char -> Char
String  :: [Char]

We'll get back another String, except capitalized.

By the way, that ugly-ish filter can be replaced made prettier with by making it use arrows :) (Think of these like more structured functions)

map (map toUpper) . filter $ elem 'p' &&& elem 'q' >>> arr (not . uncurry (||))

Gratuitousness? Maybe, but kinda cool.