commit c0b5ee3d1055f53ff16474a01e2b7327a8c2b6c6
Author: Rüdiger Diedrich <hallo@rdiedri.ch>
Date:   Wed Jan 17 15:00:57 2024 +0100

    init brc.exs

diff --git a/brc.exs b/brc.exs
new file mode 100644
index 0000000..9196215
--- /dev/null
+++ b/brc.exs
@@ -0,0 +1,39 @@
+Mix.install([
+			{:flow, "~> 1.2.4"},
+			{:ex_cldr_collation, "~> 0.7.2"}
+])
+
+defmodule Brc do
+	require Logger
+	
+  def run(path) do
+    for {city, [min, max, mean]} <- parse_file(path) do
+      "#{city}=#{min}/#{max}/#{Float.round(mean, 1)}"
+    end
+    |> Enum.sort(Cldr.Collation)
+    |> Enum.join(",")
+    |> then(fn out -> "{" <> out <> "}" end)
+    |> IO.puts()
+  end
+
+  def parse_file(path) do
+    Logger.info("parse file #{path}")
+
+		File.stream!(path)
+		|> Flow.from_enumerable()
+		|> Flow.map(&parse_line/1)
+		|> Flow.partition()
+    |> Flow.reduce(fn -> %{} end, fn {city, temp}, acc ->
+      Map.update(acc, city, [temp, temp, temp], fn [prev_min, prev_max, mean] ->
+        [min(prev_min, temp), max(prev_max, temp), (mean + temp) / 2]
+      end)
+    end)
+  end
+
+  def parse_line(line) do
+    [city, temp] = String.trim(line) |> String.split(";")
+    {city, String.to_float(temp)}
+  end
+end
+
+Brc.run("./priv/data.txt")