Enumeration

Section

get_id = & &1.id
& &1.id

grab_id = fn person_param ->
  person_param.id
end

person = %{
  id: 2,
  name: "Deltuh"
}

grab_id.(person)

get_id.(person)

defmodule Person do
  def get_id(person) do
    person.id
  end
end

Enum.map([person, person, person], fn element -> Person.get_id(element) end)

1..10_000_000_000_000_000_000_000_000_000_000_000_000_000_000_000

Enum.map([1, 2, 3], fn elem -> IO.inspect(elem) end)

Enum.map(1..10, fn elem -> elem * 2 end)

Enum.filter(1..10, fn elem -> rem(elem, 2) == 0 end)

Enum.reduce(1..10, fn element, accumulator -> element + accumulator end)

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10

map = %{existing_key: "value"}

%{map | existing_key: "new value"}

new_map = Map.put(map, :my_key, "my value")

Enum.map(1..10, fn integer ->
  %{"#{integer}" => integer}
end)

flowchart LR
Collection --> Filter --> List[List with the same # of elements or fewer]

flowchart LR
Collection --> Map --> List[List with the same # of elements]

flowchart LR
Collection --> Reduce --> ElixirValue

Enum.reduce(1..10, %{}, fn integer, accumulator -> Map.put(accumulator, "#{integer}", integer) end)

Fizzbuzz Examples

defmodule FizzBuzz do
  @doc """
  FizzBuzz.
  
  ## Examples
  
    iex> FizzBuzz.run(1..15)
    [1, 2, "fizz", 4, "buzz", "fizz", 7, 8, "fizz", "buzz", 11, "fizz", 13, 14, "fizzbuzz"]
  
    iex> FizzBuzz.run(10..15)
    ["buzz", 11, "fizz", 13, 14, "fizzbuzz"]
  """
  def run(range) do
    Enum.map(range, fn integer ->
      case {rem(integer, 3), rem(integer, 5)} do
        {0, 0} -> "fizzbuzz"
        {0, _} -> "fizz"
        {_, 0} -> "buzz"
        _ -> integer
      end
    end)
  end

  def run(range) do
    Enum.map(range, fn number ->
      divisable_by_three = rem(number, 3) == 0
      divisable_by_five = rem(number, 5) == 0

      case {divisable_by_three, divisable_by_five} do
        {true, true} -> "fizzbuzz"
        {true, false} -> "fizz"
        {false, true} -> "buzz"
        _ -> "#{number}"
      end
    end)
  end

  def run(range) do
    Enum.map(range, &number_label/1)
    # Enum.map(range, fn element -> number_label(element) end)
  end

  defp number_label(number) do
    divisable_by_three = rem(number, 3) == 0
    divisable_by_five = rem(number, 5) == 0

    case {divisable_by_three, divisable_by_five} do
      {true, true} -> "fizzbuzz"
      {true, false} -> "fizz"
      {false, true} -> "buzz"
      _ -> "#{number}"
    end
  end
end

FizzBuzz.run(1..15)