Document Tools

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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Document Tools

You’re going to create a Document module which provides some convenient function for working with text files.

Once you have a working solution, consider how you can optimize it to reduce how much of a file you load into memory.

Example Solution

defmodule Document do
  def word_count(file_name) do
    File.stream!(file_name)
    |> Stream.map(fn line ->
      line |> String.split(" ", trim: true) |> Enum.count()
    end)
    |> Enum.sum()
  end

  def line_count(file_name) do
    file = File.open!(file_name)
    count = count_lines(file)
    File.close(file)
    count
  end

  defp count_lines(file, count \\ 0) do
    case IO.read(file, :line) do
      :eof -> count
      _ -> count_lines(file, count + 1)
    end
  end

  def add_line_numbers(file_name) do
    lined_content =
      File.stream!(file_name)
      |> Stream.with_index()
      |> Stream.map(fn {line, index} -> "#{index + 1}. #{line}" end)
      |> Enum.join("")

    File.write!(file_name, lined_content)
  end
end

defmodule Document do
  @moduledoc """
  Documentation for `Document` module.
  """

  @doc ~S"""
  Count the number of words in a document.

  ## Examples

      Any sequence of characters separated by a space will be considered a word.

      iex> File.write("word_count.txt", "one two three")
      iex> Document.word_count("word_count.txt")
      3

      Ensure your solution ignores newline characters.

      iex> File.write("word_count.txt", "one\ntwo\nthree")
      iex> Document.word_count("word_count.txt")
      3
  """
  def word_count(file_name) do
  end

  @doc ~S"""
  Count the number of words in a document.

  ## Examples

      iex> File.write("line_count.txt", "line1\nline2\nline3\n")
      iex> Document.line_count("line_count.txt")
      3
  """
  def line_count(file_name) do
  end

  @doc ~S"""
  Add line numbers formatted as "X. rest of line" to an existing file.

  ## Examples

      iex> File.write("add_line_numbers.txt", "one\ntwo\nthree")
      iex> Document.add_line_numbers("add_line_numbers.txt")
      iex> File.read!("add_line_numbers.txt")
      "1. one\n2. two\n3. three"
  """
  def add_line_numbers(file_name) do
  end
end

Mark As Completed

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

save_name =
  case Path.basename(__DIR__) do
    "reading" -> "document_tools_reading"
    "exercises" -> "document_tools_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 document-tools-exercise
$ git add .
$ git commit -m "finish document tools exercise"
$ git push origin document-tools-exercise

Create a pull request from your document-tools-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.

If you are interested in joining the next academy cohort, sign up here to receive more news when it is available.

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