2016 Update

Task/Ludic-numbers/Elixir/ludic-numbers.elixir

@@ -1,26 +1,21 @@
 defmodule Ludic do
-  def numbers, do: numbers(100000)
-
-  def numbers(n) when is_integer(n) do
+  def numbers(n \\ 100000) do
     [h|t] = Enum.to_list(1..n)
     numbers(t, [h])
   end
 
   defp numbers(list, nums) when length(list) < hd(list), do: Enum.reverse(nums, list)
-  defp numbers(list, nums) do
-    h = hd(list)
-    ludic = Enum.with_index(list) |>
-            Enum.filter_map(fn{_,i} -> rem(i,h)!=0 end, fn{n,_} -> n end)
-    numbers(ludic, [h | nums])
+  defp numbers([h|_]=list, nums) do
+    Enum.drop_every(list, h) |> numbers([h | nums])
   end
 
   def task do
     IO.puts "First 25 : #{inspect numbers(200) |> Enum.take(25)}"
     IO.puts "Below 1000: #{length(numbers(1000))}"
     tuple = numbers(25000) |> List.to_tuple
-    IO.puts "2000..2005th: #{ inspect Enum.map(1999..2004, fn i -> elem(tuple, i) end) }"
+    IO.puts "2000..2005th: #{ inspect for i <- 1999..2004, do: elem(tuple, i) }"
     ludic = numbers(250)
-    triple = for x<-ludic, Enum.member?(ludic, x+2), Enum.member?(ludic, x+6), do: [x, x+2, x+6]
+    triple = for x <- ludic, x+2 in ludic, x+6 in ludic, do: [x, x+2, x+6]
     IO.puts "Triples below 250: #{inspect triple, char_lists: :as_lists}"
   end
 end