Counting Votes

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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Counting Votes

You’re creating a voting system. Voters are entered in a list of votes. You will be given a specific vote to count.

For example, you might take a class vote of cats vs dogs vs birds to decide which animal is most popular.

flowchart
D1[dogs]
D2[dogs]
D3[dogs]
C1[cats]
C2[cats]
B1[birds]

We’ll determine the number of votes for a single value. For example, there are 3 dogs.

flowchart
D1[dogs]
D2[dogs]
D3[dogs]
C1[cats]
C2[cats]
B1[birds]

style D1 fill:lightgreen
style D2 fill:lightgreen
style D3 fill:lightgreen

So we would return 3 votes for dogs.

Votes.count([:dogs, :dogs, :dogs, :cats, :cats, :birds], :dogs)
3

defmodule Votes do
  @doc """
  Count the number of votes.

  ## Examples

    iex> Votes.count([:dogs, :dogs, :dogs, :cats], :dogs)
    3

    iex> Votes.count([:dogs, :dogs, :dogs, :cats], :cats)
    1

    iex> Votes.count([:apples, :oranges, :apples, :cats], :birds)
    0
  """
  def count(votes, vote) do
  end
end

Bonus: Voter Tally

Counting each vote for dogs, cats, and birds becomes tedius. So, we instead want to determine the number of votes for each all at once.

flowchart
D1[dog]
D2[dog]
D3[dog]
C1[cat]
C2[cat]
B1[bird]

style D1 fill:lightgreen
style D2 fill:lightgreen
style D3 fill:lightgreen

style C1 fill:orange
style C2 fill:orange
style B1 fill:lightblue

There are 3 dogs, 2 cats, and 1 bird.

defmodule VoterTally do
  @doc """
  Determine the number of votes for each option received.

  ## Examples

    iex> VoterTally.tally([:dog, :dog, :cat, :cat, :cat, :bird])
    %{dog: 2, cat: 3, bird: 1}
  """
  def tally(votes) do
  end
end

Mark As Completed

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

save_name =
  case Path.basename(__DIR__) do
    "reading" -> "counting_votes_reading"
    "exercises" -> "counting_votes_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 counting-votes-exercise
$ git add .
$ git commit -m "finish counting votes exercise"
$ git push origin counting-votes-exercise

Create a pull request from your counting-votes-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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