Java: Max/min value in an array?

Question

It's trivial to write a function to determine the min/max value in an array, such as:

/**
 * 
 * @param chars
 * @return the max value in the array of chars
 */
private static int maxValue(char[] chars) {
 int max = chars[0];
 for (int ktr = 0; ktr < chars.length; ktr++) {
  if (chars[ktr] > max) {
   max = chars[ktr];
  }
 }
 return max;
}

but isn't this already done somewhere?

Answer 1

Yes, it's done in the Collections class. Note that you will need to convert your primitive char array to a Character[] manually.

A short demo:

import java.util.*;

public class Main {

    public static Character[] convert(char[] chars) {
        Character[] copy = new Character[chars.length];
        for(int i = 0; i < copy.length; i++) {
            copy[i] = Character.valueOf(chars[i]);
        }
        return copy;
    }

    public static void main(String[] args) {
        char[] a = {'3', '5', '1', '4', '2'};
        Character[] b = convert(a);
        System.out.println(Collections.max(Arrays.asList(b)));
    }
}

Answer 2

Here's a utility class providing min/max methods for primitive types: Primitives.java

Answer 3

Using Commons Lang (to convert) + Collections (to min/max)

import java.util.Arrays;
import java.util.Collections;

import org.apache.commons.lang.ArrayUtils;

public class MinMaxValue {

    public static void main(String[] args) {
        char[] a = {'3', '5', '1', '4', '2'};

        List b = Arrays.asList(ArrayUtils.toObject(a));

        System.out.println(Collections.min(b));
        System.out.println(Collections.max(b));
   }
}

Answer 4

The Google Guava library has min and max methods in its Chars, Ints, Longs, etc. classes.

So you can simply use:

Chars.min(myarray)

No conversions are required and presumably it's efficiently implemented.