Concurrent Word Count

Mix.install([
  {:jason, "~> 1.4"},
  {:kino, "~> 0.8.0", override: true},
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"}
])

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Concurrent Word Count

Given a list of documents, use the Task module to concurrently find the total word count of every document combined.

For our purposes, a word will be any sequence of characters separated by a space. You do not have to handle invalid words, punctuation, or other special cases.

document = """
This is my document document
"""

String.split(document, " ", trim: true)

Example Solution

defmodule WordCount do
  def individual_count(documents) do
    tasks =
      Enum.map(documents, fn document ->
        Task.async(fn ->
          document |> String.split(" ", trim: true) |> Enum.count()
        end)
      end)

    Task.await_many(tasks)
  end

  def total_count(documents) do
    documents |> individual_count() |> Enum.sum()
  end
end

Implement the WordCount module as documented below.

defmodule WordCount do
  @moduledoc """
  Documentation for `WordCount`.
  """

  @doc """
  Concurrently count the number of words in each document.

  ## Examples

      iex> WordCount.individual_count(["document one", "document two"])
      [2, 2]
  """
  def individual_count(documents) do
  end

  @doc """
  Concurrently count the number of words in each document and return
  the combined count.

  iex> WordCount.total_count(["document one", "document two"])
  4
  """
  def total_count(documents) do
  end
end

Mark As Completed

file_name = Path.basename(Regex.replace(~r/#.+/, __ENV__.file, ""), ".livemd")

save_name =
  case Path.basename(__DIR__) do
    "reading" -> "concurrent_word_count_reading"
    "exercises" -> "concurrent_word_count_exercise"
  end

progress_path = __DIR__ <> "/../progress.json"
existing_progress = File.read!(progress_path) |> Jason.decode!()

default = Map.get(existing_progress, save_name, false)

form =
  Kino.Control.form(
    [
      completed: input = Kino.Input.checkbox("Mark As Completed", default: default)
    ],
    report_changes: true
  )

Task.async(fn ->
  for %{data: %{completed: completed}} <- Kino.Control.stream(form) do
    File.write!(
      progress_path,
      Jason.encode!(Map.put(existing_progress, save_name, completed), pretty: true)
    )
  end
end)

form

Commit Your Progress

Run the following in your command line from the curriculum folder to track and save your progress in a Git commit. Ensure that you do not already have undesired or unrelated changes by running git status or by checking the source control tab in Visual Studio Code.

$ git checkout -b concurrent-word-count-exercise
$ git add .
$ git commit -m "finish concurrent word count exercise"
$ git push origin concurrent-word-count-exercise

Create a pull request from your concurrent-word-count-exercise branch to your solutions branch. Please do not create a pull request to the DockYard Academy repository as this will spam our PR tracker.

DockYard Academy Students Only:

Notify your teacher by including @BrooklinJazz in your PR description to get feedback. You (or your teacher) may merge your PR into your solutions branch after review.

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