Add Linear Search in Elixir

archive/e/elixir/linear-search.ex

@@ -0,0 +1,41 @@
+defmodule LinearSearch do
+  @doc """
+  Searches for an integer in a list of integers from the argument list.
+
+  Expects two arguments: a comma-separated list of integers (e.g. `"1, 4, 5, 11"`)
+  and the integer to find (e.g. `"11"`).
+
+  Returns `{:ok, true}` if found, `{:ok, false}` if not, and `:error` if arg is invalid.
+  """
+  @spec main(argv :: list(String.t())) :: {:ok, boolean()} | :error
+  def main([list, target]) do
+    with {:ok, list}  <- parse_list(list),
+         {target, ""} <- Integer.parse(target)
+    do
+      {:ok, Enum.member?(list, target)} 
+    else
+      _ -> :error
+    end
+  end 
+  def main(_), do: :error
+
+  @spec parse_list(str :: String.t()) :: {:ok, list(integer())} | :error
+  defp parse_list(""), do: :error
+  defp parse_list(str) do
+    str
+    |> String.split(",")
+    |> Enum.map(&String.trim/1)
+    |> Enum.reduce_while({:ok, []}, fn n, {:ok, acc} ->
+      case Integer.parse(n) do
+        {n, ""} -> {:cont, {:ok, [n | acc]}}
+        _       -> {:halt, :error}
+      end
+    end)
+  end
+end
+
+case LinearSearch.main(System.argv()) do
+  {:ok, res} -> IO.puts(res)
+  _ -> IO.puts("Usage: please provide a list of integers (\"1, 4, 5, 11, 12\") and the integer to find (\"11\")")
+end
+