Sorting by Functions in CLIPS

Our example demonstrates how to sort collections using custom comparison functions in Java. We’ll explore sorting strings by their length and sorting custom objects.

import java.util.*;

public class SortingByFunctions {
    public static void main(String[] args) {
        List<String> fruits = new ArrayList<>(Arrays.asList("peach", "banana", "kiwi"));

        // We implement a comparison function for string lengths using a Comparator
        Comparator<String> lenComparator = (a, b) -> Integer.compare(a.length(), b.length());

        // Now we can call Collections.sort with this custom comparator to sort fruits by name length
        Collections.sort(fruits, lenComparator);
        System.out.println(fruits);

        // We can use the same technique to sort a list of values that aren't built-in types
        class Person {
            String name;
            int age;

            Person(String name, int age) {
                this.name = name;
                this.age = age;
            }

            @Override
            public String toString() {
                return "{" + name + " " + age + "}";
            }
        }

        List<Person> people = Arrays.asList(
            new Person("Jax", 37),
            new Person("TJ", 25),
            new Person("Alex", 72)
        );

        // Sort people by age using Collections.sort with a custom Comparator
        Collections.sort(people, (a, b) -> Integer.compare(a.age, b.age));
        System.out.println(people);
    }
}

In this Java example, we use Comparator interfaces and the Collections.sort() method to achieve custom sorting. The Comparator interface in Java is similar to the comparison function in the original example.

For sorting strings by length, we create a Comparator<String> using a lambda expression. This comparator compares the lengths of two strings.

For sorting custom objects (in this case, Person objects), we create another Comparator<Person> that compares the age field of two Person objects.

The Collections.sort() method is used instead of slices.SortFunc(). Java’s built-in sorting algorithms are used under the hood, which may differ from those used in the original example.

Note that in Java, we typically use ArrayList or other List implementations instead of slices. The sorting is done in-place, modifying the original list.

To run this program, save it as SortingByFunctions.java, compile it, and run it:

$ javac SortingByFunctions.java
$ java SortingByFunctions
[kiwi, peach, banana]
[{TJ 25}, {Jax 37}, {Alex 72}]

This example demonstrates how to implement custom sorting logic in Java, which is a common requirement in many programming tasks.

Sorting in CLIPS

Panic in CLIPS

Learn X By Example

Title here

Sorting by Functions in CLIPS