Elixir Set Lookup

lookup.ex

defmodule Lookup do
  @wordfile "words.txt"
  @external_resource @wordfile

  @times 1_000_000

  @words @wordfile |> File.stream! |> Enum.map(&String.strip/1)

  @hash_set Enum.into(@words, HashSet.new)
  @map_set Enum.into(@words, MapSet.new)

  def time({f, a}, expected) do
    :erlang.statistics(:runtime)
    Enum.each(0..@times, fn _ ->
      ^expected = apply(__MODULE__, f, [a])
    end)
    {_, cpu_elapsed} = :erlang.statistics(:runtime)
    cpu_elapsed_ms = cpu_elapsed * 1000
    IO.puts "#{f} took #{cpu_elapsed_ms}µs to look up '#{a}' #{@times} times, #{cpu_elapsed_ms / @times} µs/lookup"
  end

  def valid_word, do: List.last(@words)

  def hash_set_member?(word), do: Set.member?(@hash_set, word)
  def map_set_member?(word), do: Set.member?(@map_set, word)

  IO.puts "Compiling function clauses, this'll take a second..."
  Enum.each @words, fn word ->
    def member?(unquote(word)), do: true
  end
  def member?(_), do: false
end

IO.puts "...done"

invalid_word = "an invalid word"

Lookup.time({:hash_set_member?, Lookup.valid_word}, true)
Lookup.time({:hash_set_member?, invalid_word}, false)

Lookup.time({:map_set_member?, Lookup.valid_word}, true)
Lookup.time({:map_set_member?, invalid_word}, false)

Lookup.time({:member?, Lookup.valid_word}, true)
Lookup.time({:member?, invalid_word}, false)

Hi Michael,

do these numbers match yours?

$ wc -l words.txt 

21110 words.txt

$ elixir lookup.exs 

Compiling function clauses, this'll take a second...
...done
hash_set_member? took 130000µs to look up 'zymase' 1000000 times, 0.13 µs/lookup
hash_set_member? took 350000µs to look up 'an invalid word' 1000000 times, 0.35 µs/lookup
map_set_member? took 159480000µs to look up 'zymase' 1000000 times, 159.48 µs/lookup
map_set_member? took 120330000µs to look up 'an invalid word' 1000000 times, 120.33 µs/lookup
member? took 240000µs to look up 'zymase' 1000000 times, 0.24 µs/lookup
member? took 200000µs to look up 'an invalid word' 1000000 times, 0.2 µs/lookup