Java Median median(final double... values)

Description

Calculates and returns the median of an array of double.

License

Open Source License

Parameter

Parameter	Description
values	an array of doubles to calculate the median of.

Return

the median of the provided array of doubles.

Declaration

public static double median(final double... values) 

Method Source Code

//package com.java2s;
/*/*  w w  w . j a  va2s  .com*/
 * Copyright 2007-2010 Tom Castle & Lawrence Beadle
 * Licensed under GNU General Public License
 * 
 * This file is part of EpochX: genetic programming software for research
 * 
 * EpochX is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * EpochX is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with EpochX. If not, see <http://www.gnu.org/licenses/>.
 * 
 * The latest version is available from: http:/www.epochx.org
 */

import java.util.Arrays;

public class Main {
    /**
     * Calculates and returns the median of an array of <code>double</code>. The
     * provided <code>values</code>argument must not be null nor an empty array.
     * 
     * @param values an array of doubles to calculate the median of.
     * @return the median of the provided array of doubles.
     */
    public static double median(final double... values) {
        if ((values != null) && (values.length != 0)) {
            // Sort the array.
            Arrays.sort(values);

            // Pick out the middle value.
            final int medianIndex = (int) Math.floor(values.length / 2);
            double median = values[medianIndex - 1];

            // There might have been an even number - use average of 2 medians.
            if ((values.length % 2) == 0) {
                median += values[medianIndex];
                median = median / 2;
            }

            return median;
        } else {
            throw new IllegalArgumentException("cannot calculate median of null or empty array of values");
        }
    }

    /**
     * Calculates and returns the median of an array of <code>int</code>. The
     * provided <code>values</code>argument must not be null nor an empty array.
     * 
     * @param values an array of int to calculate the median of.
     * @return the median of the provided array of ints.
     */
    public static double median(final int... values) {
        if ((values != null) && (values.length != 0)) {
            // Sort the array.
            Arrays.sort(values);

            // Pick out the middle value.
            final int medianIndex = (int) Math.floor(values.length / 2);
            int median = values[medianIndex - 1];

            // There might have been an even number - use average of 2 medians.
            if ((values.length % 2) == 0) {
                median += values[medianIndex];
                median = median / 2;
            }

            return median;
        } else {
            throw new IllegalArgumentException("cannot calculate median of null or empty array of values");
        }
    }
}

Related

1. median(double[] x)
2. median(double[] x)
3. median(double[][] values)
4. median(final ArrayList values)
5. median(final double... in)
6. median(final double[] values)
7. median(final int[] values)
8. median(float a, float b, float c)
9. median(float[] vals)