word_counter.ex

"""
  You should add Flow as a dependency to your Mix project configuration:
  
  mix.exs:
  
  defp deps do
    [
      ...,
      {:flow, "~> 0.14.2"},
      ...
    ]
  end
  
## Examples:

  iex> WordCounter.flow_wordcount("lib/word_counter.ex")
  %{
    "Flow.reduce(" => 1,
    "&" => 3,
    "word," => 6,
    "Flow.flat_map(&String.split/1)" => 1,
    "%{}" => 1,
    "Flow.partition()" => 1,
    "Map.update(map," => 3,
    "Enum.flat_map(&String.split/1)" => 1,
    "&1" => 3,
    "Flow.from_enumerable()" => 1,
    "lazy_wordcount(filepath)" => 1,
    "def" => 3,
    "end" => 4,
    "eager_wordcount(filepath)" => 1,
    "File.read!(filepath)" => 1,
    "File.stream!(filepath)" => 2,
    "->" => 4,
    "Enum.reduce(%{}," => 2,
    "end," => 1,
    "WordCounter" => 1,
    "Enum.into(%{})" => 1,
    "defmodule" => 1,
    "do" => 4,
    "flow_wordcount(filepath)" => 1,
    "fn" => 4,
    "1," => 3,
    "+" => 3,
    "end)" => 3,
    "Stream.flat_map(&String.split/1)" => 1,
    "|>" => 10,
    "1)" => 3,
    "String.split(\"\\n\")" => 1,
    "map" => 3
  }

"""
defmodule WordCounter do
  def eager_wordcount(filepath) do
    File.read!(filepath)
    |> String.split("\n")
    |> Enum.flat_map(&String.split/1)
    |> Enum.reduce(%{}, fn word, map -> Map.update(map, word, 1, & &1 + 1) end)
  end

  def lazy_wordcount(filepath) do
    File.stream!(filepath)
    |> Stream.flat_map(&String.split/1)
    |> Enum.reduce(%{}, fn word, map -> Map.update(map, word, 1, & &1 + 1) end)
  end

  def flow_wordcount(filepath) do
    File.stream!(filepath)
    |> Flow.from_enumerable()
    |> Flow.flat_map(&String.split/1)
    |> Flow.partition()
    |> Flow.reduce(
      fn -> %{} end,
      fn word, map -> Map.update(map, word, 1, & &1 + 1) end)
    |> Enum.into(%{})
  end
end