Kotlin – Sort List of Objects with Kotlin Comparator Example

This tutorial shows you way to Sort List of Objects by implementing Comparator example.

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I. Technology

– Java 1.8
– Kotlin 1.1.2

II. Overview

1. Goal

Sort list of three MyDate(year,month,day) objects.

2. Steps to do

– Implement Comparator interface for the class that you use for handling sorting.
– Override compare(object1: T, object2: T) method and:
+ return zero if object1 is equal object2
+ a negative number if object1 is less than object2
+ a positive number if object1 is greater than object2
– Use sortedWith(comparator: Comparator) method that returns a List.

III. Practice

1. Create Class for objects to be sorted

2. Create Class for handling sorting

3. Create test function

We can also use fast way of creating Comparator with compareBy method:

Calling sortedWith() method now becomes:

4. Run & check Result

By grokonez | August 29, 2017.

Last updated on December 15, 2017.

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