In Haskell, I got this string "bbbbffff", and I want to get a list in this form:
['b','b','b','b','f','f','f','f']
I think that I can use map, but sincerely, I don't know how to begin, and are a lot of things that I do not understand in Haskell.
Thanks in advance.
By default, a String is already a [Char] (see specification):
A string is a list of characters:
type String = [Char]
They simply don't print as ['b','b','b',...] because [Char] and String is the same type and therefore indistinguishable and must be shown the same way. Indeed, if you input your list you'll see it formatted as a string:
Prelude> 42
42
Prelude> [1,2,3]
[1,2,3]
Prelude> ['b','b','b','b','f','f','f','f']
"bbbbffff"
This means that you can immediately pass it to any list function, without having to do anything with it:
myLength :: [Char] -> Int
myLength (c:rest) = 1 + myLength rest
myLength [] = 0
-- Prints 11
main = print (myLength "hello world")
There are other textual data types like Data.Text, but these are for more advanced use and must be explicitly enabled and used.
'a' is a Char and "a" is a [Char]. ord does not work on lists. If you want to do this to each character in the list, you can use map: map (\c -> ord c + 1) "foobar" == [103,112,112,99,98,115]
