The List module provides a set of functions that operate on lists.
| | # |
| | # Concatenate lists |
| | # |
| | iex> [1,2,3] ++ [4,5,6] |
| | [1, 2, 3, 4, 5, 6] |
| | # |
| | # Flatten |
| | # |
| | iex> List.flatten([[[1], 2], [[[3]]]]) |
| | [1, 2, 3] |
| | # |
| | # Folding (like reduce, but can choose direction) |
| | # |
| | iex> List.foldl([1,2,3], "", fn value, acc -> "#{value}(#{acc})" end) |
| | "3(2(1()))" |
| | iex> List.foldr([1,2,3], "", fn value, acc -> "#{value}(#{acc})" end) |
| | "1(2(3()))" |
| | # |
| | # Updating in the middle (not a cheap operation) |
| | # |
| | iex> list = [ 1, 2, 3 ] |
| | [ 1, 2, 3 ] |
| | iex> List.replace_at(list, 2, "buckle my shoe") |
| | [1, 2, "buckle my shoe"] |
| | # |
| | # Accessing tuples within lists |
| | # |
| | iex> kw = [{:name, "Dave"}, {:likes, "Programming"}, {:where, "Dallas", "TX"}] |
| | [{:name, "Dave"}, {:likes, "Programming"}, {:where, "Dallas", "TX"}] |
| | iex> List.keyfind(kw, "Dallas", 1) |
| | {:where, "Dallas", "TX"} |
| | iex> List.keyfind(kw, "TX", 2) |
| | {:where, "Dallas", "TX"} |
| | iex> List.keyfind(kw, "TX", 1) |
| | nil |
| | iex> List.keyfind(kw, "TX", 1, "No city called TX") |
| | "No city called TX" |
| | iex> kw = List.keydelete(kw, "TX", 2) |
| | [name: "Dave", likes: "Programming"] |
| | iex> kw = List.keyreplace(kw, :name, 0, {:first_name, "Dave"}) |
| | [first_name: "Dave", likes: "Programming"] |