An elixir function to calculate the nth prime number

prime_number.ex

defmodule PrimeNumber do
  def is_prime(2), do: true
  def is_prime(number) do
    not Enum.any?(2..number-1, fn x -> rem(number, x) == 0 end)
  end

  def prime(n) do
    Stream.interval(1)
    |> Stream.filter(&is_prime/1)
    |> Enum.take(n)
  end
end

1..100
|> Enum.filter(&PrimeNumber.is_prime/1)
|> IO.inspect()

PrimeNumber.prime(25)
|> IO.inspect()


## Another version taken from elixirforum.com
defmodule Prime do
  def nth_prime(n) do
    Stream.iterate(1, &(&1 + 1))
    |> Stream.filter(&prime?(&1))
    |> Stream.with_index(1)
    |> Enum.find(fn {_prime, x} -> x == n end)
  end

  def prime?(1), do: false
  def prime?(2), do: true
  def prime?(3), do: true
  def prime?(5), do: true
  def prime?(7), do: true
  def prime?(n) when rem(n, 2) == 0, do: false
  def prime?(n) do
    limit = [7, round(:math.sqrt(n))] |> Enum.max

    Stream.iterate(3, &(&1 + 2))
    |> Stream.take_while(fn x -> x <= limit end)
    |> Stream.filter(fn x -> rem(n,x) == 0 end)
    |> Enum.empty?
  end
end