For example I have the String "Hello what a nice day" it is supposed to convert to this: "Hello What A Nice Day".

I want to convert it with a map.

I have tried:

upperFirst list = map (\a -> toUpper a) . filter(\(x:sx:xs) -> isSpace x && isLower sx) list

This way I wanna check, if my current char is " " and the char behind it is in lower case. But obviously it doesn't work.

Maybe someone can help me and explain it for me.

CodePudding user response：

You can work with words :: String -> [String] and unwords :: [String] -> String to split a string into a list of strings and transfer it back. Then you only need to convert each individual word, so:

upperFirst :: String -> String
upperFirst = unwords. … . words

where I leave the …-part as an exercise.