From 4226200b433002de1fbe92ba3e7e2ffbbe632142 Mon Sep 17 00:00:00 2001 From: Gunnar Morling Date: Thu, 28 Dec 2023 11:44:58 +0100 Subject: =?UTF-8?q?=F0=9F=8F=86=20Initial=20import?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../java/dev/morling/onebrc/CalculateAverage.java | 44 ++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 src/main/java/dev/morling/onebrc/CalculateAverage.java (limited to 'src/main/java/dev/morling/onebrc/CalculateAverage.java') diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage.java b/src/main/java/dev/morling/onebrc/CalculateAverage.java new file mode 100644 index 0000000..7672d75 --- /dev/null +++ b/src/main/java/dev/morling/onebrc/CalculateAverage.java @@ -0,0 +1,44 @@ +/* + * Copyright 2023 The original authors + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package dev.morling.onebrc; + +import static java.util.stream.Collectors.averagingDouble; +import static java.util.stream.Collectors.groupingBy; + +import java.io.IOException; +import java.nio.file.Files; +import java.nio.file.Paths; +import java.util.Map; +import java.util.TreeMap; +import java.util.stream.Collectors; + +public class CalculateAverage { + + private static final String FILE = "./measurements.txt"; + + public static void main(String[] args) throws IOException { + Map measurements = Files.lines(Paths.get(FILE)) + .limit(10_000_000) + .map(l -> l.split(";")) + .collect(groupingBy(m -> m[0], averagingDouble(m -> Double.parseDouble(m[1])))); + + measurements = new TreeMap<>(measurements.entrySet() + .stream() + .collect(Collectors.toMap(e -> e.getKey(), e -> Math.round(e.getValue() * 10.0) / 10.0))); + + System.out.println(measurements); + } +} -- cgit v1.2.3