Document Tools

Mix.install([
  {:jason, "~> 1.4"},
  {:kino, "~> 0.9", 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

Commit Your Progress

DockYard Academy now recommends you use the latest Release rather than forking or cloning our repository.

Run git status to ensure there are no undesirable changes. Then run the following in your command line from the curriculum folder to commit your progress.

$ git add .
$ git commit -m "finish Document Tools exercise"
$ git push

We’re proud to offer our open-source curriculum free of charge for anyone to learn from at their own pace.

We also offer a paid course where you can learn from an instructor alongside a cohort of your peers. We will accept applications for the June-August 2023 cohort soon.

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