Java Collection Mean getMean(final Collection collection)

Description

get Mean

License

Apache License

Declaration

public static <T extends Number> double getMean(final Collection<T> collection) 

Method Source Code

//package com.java2s;
/**//from   w ww .j a  v a  2s . c  o  m
 * Copyright (C) 2012 Philip W. Sorst <philip@sorst.net>
 * and individual contributors as indicated
 * by the @authors tag.
 *
 * 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.
 */

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;

import java.util.List;

public class Main {
    public static <T extends Number> double getMean(final Collection<T> collection) {

        final int size = collection.size();

        final List<T> sorted = new ArrayList<T>(collection);
        Collections.sort(sorted, new Comparator<T>() {

            @Override
            public int compare(final T n1, final T n2) {

                return (int) Math.signum(n2.doubleValue() - n1.doubleValue());
            }
        });

        if (size % 2 == 0) {
            return (sorted.get(size / 2).doubleValue() + sorted.get(size / 2 - 1).doubleValue()) / 2;
        } else {
            return sorted.get(size / 2).doubleValue();
        }
    }
}

Related

1. calculateMean(Collection values)
2. calculateMean(Collection values)
3. calculateMean(Collection values)
4. getMean(Collection data)
5. getMean(Collection cluster)
6. getVariance(Collection data, Number mean)
7. mean(Collection coll)
8. mean(Collection nums)
9. mean(Collection data)