Disclaimer: I’m going through some old posts that were in draft and publishing one’s which look relatively complete in case they’re of use: This post may not be 100% complete but does give a good overview of Elixir collections.

Lists in Elixir are implemented as linked lists which handle handle different types.

[3, "Three" :three]

Prepending to a list is faster than appending

list = [3, "Three" :three]
["pre" | list]

Appending

list = [3, "Three" :three]
list ++ ["post"]

List concat

[3, "Three" :three] ++ ["four", :4, 4]

List subtraction,

[2] -- [2.0]

Head and tail

hd [3, "Three" :three]
tl [3, "Three" :three]

Pattern matching

We can split the head an tail using Z

[head | tail] = [3.14, :pie, "Apple"]

The equivalent of a dictionary known as keyword lists in Elixir

[foo: "bar", hello: "world"]
[{:foo, "bar"}, {:hello, "world"}]

Keys can be atoms, keys are ordered and do not have to be unique

Maps

Unlike keyword lists they allows keys of any type and are unordered the syntax for a ,ap is %{}

map = %{:foo => "bar", "hello" => :world}