Keywords, functions, tuples

import IEx.Helpers

Keywords

list = [{"one", 1}, {"two", 2}]

[{"one", 1}, {"two", 2}]

list = [{:one, 1}, {:two, 2}]

[one: 1, two: 2]

# keyword data
# looks like a map
[one: 1, two: 2]

[one: 1, two: 2]

Tuple

{:arg1, :arg2, :options} |> Tuple.to_list() |> Enum.count()

3

# {:arg1, :arg2, [{:fast, true}, {:cheap, true}]}
# {:arg1, :arg2, [fast: true, cheap: true]}

# fast: true, cheap: true -> keyword
# we can omit the bracket if the last item is keyword

{:arg1, :arg2, fast: true, cheap: true}

{:arg1, :arg2, [fast: true, cheap: true]}

{:arg1, :arg2, fast: true, cheap: true} |> Tuple.to_list() |> Enum.count()

3

Functions

defmodule Args do
  def whats_going_on(first, options) do
    # inspected value is a keyword
    "first: #{first}, options: #{inspect(options)}"
  end
end

{:module, Args, <<70, 79, 82, 49, 0, 0, 7, ...>>, {:whats_going_on, 2}}

import Args

Args

whats_going_on(:one, :two)

"first: one, options: :two"

whats_going_on(:one, [{:one, 1}, {:two, 2}])

"first: one, options: [one: 1, two: 2]"

whats_going_on(:one, fast: true, cheap: true, reliable: true)

"first: one, options: [fast: true, cheap: true, reliable: true]"

exports(Args)

whats_going_on/2     

kw = [one: 1, two: 2]
# access behavior
kw[:one]

1