Grouping collections

Kotlin's collection framework allows you to group collections based on your requirements. For example, if you have a list of strings and want to group them with respect to their size, you can easily do that with the help of the groupBy function, which groups a collection based on the logic provided and returns Map with that group of collections.

So, the following is a short example:

fun main(args: Array<String>) { 
    val list = 1.rangeTo(50).toList() 
 
    println(list.groupBy { it%5 }) 
} 

So, what we did here is as follows: we created a list of Int containing numbers from 1 to 50 (both inclusive) then, we tried to group them based on their remnants when divided by 5.

So, there should be five groups, from 0 to 5, and each of them should contain 10 numbers. Let's check the following output to see if that happened or not:

So, the groupBy function just worked as expected and returned Map<Int,List<Int>> that contained the grouped list.