https://grokonez.com/kotlin/kotlin-compare-objects-comparable-example

Kotlin – Compare Objects with Comparable Example

This tutorial shows you way to compare Objects with Comparable by an example.

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I. Technology

- Java 1.8 - Kotlin 1.1.2

II. Overview

1. Goal

First, we compare two objects Date(year:Int,month:Int,day:Int). Second, we continue to work on two Product(name:String,date:Date) objects.

2. Steps to do

- Implement Comparable interface for the class of objects you want to compare. - Override compareTo(other: T) method and: + return zero if this object is equal other + a negative number if it's less than other + a positive number if it's greater than other

III. Practice

1. Create Classes

package com.javasampleapproach.objcomparision
import kotlin.Comparable
data class Date(val year: Int, val month: Int, val day: Int) : Comparable {
override fun compareTo(other: Date) = when {
	year != other.year -> year - other.year
	month != other.month -> month - other.month
	else -> day - other.day
}

}

Product class includes Date field (implemented Comparable interface), so you can compare two Date objects inside using operator <,>,==.

More at:

https://grokonez.com/kotlin/kotlin-compare-objects-comparable-example

Kotlin – Compare Objects with Comparable Example

#kotlin #comparable