Data commit

Task/Hash-join/Elixir/hash-join.elixir

@@ -0,0 +1,20 @@
+defmodule Hash do
+  def join(table1, index1, table2, index2) do
+    h = Enum.group_by(table1, fn s -> elem(s, index1) end)
+    Enum.flat_map(table2, fn r ->
+      Enum.map(h[elem(r, index2)], fn s -> {s, r} end)
+    end)
+  end
+end
+
+table1 = [{27, "Jonah"},
+          {18, "Alan"},
+          {28, "Glory"},
+          {18, "Popeye"},
+          {28, "Alan"}]
+table2 = [{"Jonah", "Whales"},
+          {"Jonah", "Spiders"},
+          {"Alan",  "Ghosts"},
+          {"Alan",  "Zombies"},
+          {"Glory", "Buffy"}]
+Hash.join(table1, 1, table2, 0) |> Enum.each(&IO.inspect &1)