Lists

Lists

Lists are ordered collections in Elixir:

nums = [1, 2, 3, 4]
IO.puts(length(nums))   # 4

hd and tl

hd returns the head (first element), tl returns the tail (rest):

IO.puts(hd([1, 2, 3]))   # 1
IO.puts(length(tl([1, 2, 3])))   # 2

Concatenation with ++

a = [1, 2, 3]
b = [4, 5, 6, 7]
IO.puts(Enum.sum(a ++ b))   # 28

Your Turn

Given nums = [1, 2, 3, 4, 5]:

1. Print length(nums) → 5
2. Print hd(nums) → 1
3. Print length(tl(nums)) → 4
4. Print Enum.sum(nums ++ [6, 7]) → 28