obtaining each element of a list haskell code example

Example 1: first element in list haskell

list = [1, 2, 3]

head :: [a] -> a
head (x:_) = x

head list -- 1

Example 2: haskell list element at index

-- the "!!" operator return the n-th element from the list
-- *this is zero based

"string" !! 2 --> "r"

[10, 20, 30, 40] !! 1 --> 20