Finding the max/min value in an array of primitives using Java

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         


        

Answer 1

Here is a solution to get the max value in about 99% of runs (change the 0.01 to get a better result):

public static double getMax(double[] vals){
    final double[] max = {Double.NEGATIVE_INFINITY};

    IntStream.of(new Random().ints((int) Math.ceil(Math.log(0.01) / Math.log(1.0 - (1.0/vals.length))),0,vals.length).toArray())
            .forEach(r -> max[0] = (max[0] < vals[r])? vals[r]: max[0]);

    return max[0];
}

(Not completely serious)

Answer 2

You could easily do it with an IntStream and the max() method.

Example

public static int maxValue(final int[] intArray) {
  return IntStream.range(0, intArray.length).map(i -> intArray[i]).max().getAsInt();
}

Explanation

1. range(0, intArray.length) - To get a stream with as many elements as present in the intArray.

2. map(i -> intArray[i]) - Map every element of the stream to an actual element of the intArray.

3. max() - Get the maximum element of this stream as OptionalInt.

4. getAsInt() - Unwrap the OptionalInt. (You could also use here: orElse(0), just in case the OptionalInt is empty.)

Answer 3

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.

Answer 4

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

int [] numbers= {10,1,8,7,6,5,2};
    int a=Integer.MAX_VALUE;
    for(int c:numbers) {
        a=c<a?c:a;
        }
        
    System.out.println("Lowest value is"+a);

Answer 5

I have a little helper class in all of my applications with methods like:

public static double arrayMax(double[] arr) {
    double max = Double.NEGATIVE_INFINITY;

    for(double cur: arr)
        max = Math.max(max, cur);

    return max;
}

Answer 6

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));
   }
}

Note that Arrays.asList() wraps the underlying array, so it should not be too memory intensive and it should not perform a copy on the elements of the array.