Created
October 18, 2016 12:46
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defmodule ChainedStream do | |
# [#Function<59.77324385/2 in Stream.unfold/2>, #Function<59.77324385/2 in Stream.unfold/2>] | |
def test do | |
states = count(%{}, ["a", "b", "c"]) |> Enum.to_list | |
# [{%{"a" => 1}, ["b", "c"]}, {%{"a" => 1, "b" => 1}, | |
# ["c"]}, {%{"a" => 1, "b" => 1, "c" => 1}, []}] | |
states |> Enum.at(-1) |> elem(0) |> count(["a", "b", "d"]) | |
# [{%{"a" => 2, "b" => 1, "c" => 1}, ["b", "d"]}, | |
# {%{"a" => 2, "b" => 2, "c" => 1}, ["d"]}, | |
# {%{"a" => 2, "b" => 2, "c" => 1, "d" => 1}, []}] | |
end | |
def count(%{} = stats, things) do | |
Stream.unfold({stats, things}, &count_items/1) | |
end | |
def count_items({stats, []}), do: nil | |
def count_items({stats, [h | t] = items}) do | |
new_stats = Map.update(stats, h, 1, &(&1 + 1)) | |
{{new_stats, t}, {new_stats, t}} | |
end | |
end |
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