lec03 generic servers

lectures/03/notes.ex

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+### Streams
+
+0..1_000_000 |> Enum.map(& &1 * &1) |> Enum.filter(& rem(&1, 8) == 0) |> Enum.sum
+#                        & &1 * &1 is equivalent to
+#                        fn x -> x * x end
+
+0..1_000_000 |> Steam.map(& &1 * &1) |> Steam.filter(& rem(&1, 8) == 0) |> Enum.sum
+
+fibs = Stream.unfold({0, 1}, fn {a, b} -> {a, {b, a+b}} end)
+fibs |> Enum.take(20);
+
+# fizzbuzz infstream
+nats = Stream.iterate(1, & &1 + 1)
+#      Stream.iterate(1, fn x -> x + 1) is an inf stream because we can take up to n with no limit
+nats |> Enum.take(10)
+
+fizz = Stream.cycle(["", "", "fizz"])
+fizz |> Enum.take(10)
+buzz = Stream.cycle(["", "", "", "", "buzz"])
+buzz |> Enum.take(10)
+
+fizzbuzz = Stream.zip_with([nats, fizz, buzz], fn [n, f, b] ->
+  if f == "" && b == "", do: n,
+  else: f <> b # concat f with b
+end)