How to initiate array items using for loop in Kotlin

Question

Python allows programmers to perform such an operation:

mylist = [1, 2]
items = [value * 2 for value in namelist]

How can I achieve the same using Kotlin, I want to pass values multiplied by 2 from mylist into the array below:

val mylist = mutableListOf(1, 2)
val (first, second) = arrayOf( )

Kotlin allows us to to declare and initiate variables with one liners as below

val (first, second) = arrayOf(1, 2) that way you can call first or second as a variable. Am trying to make the equal part dynamic

Am trying to make the equal part dynamic. Are you saying you want to create these variables like first, second dynamically? — Arpit Shukla
– Arpit Shukla, Commented Jun 20, 2022 at 10:10
Creating variables at run time isn't possible. Why do you need to do that? Can you share an example? — Arpit Shukla
– Arpit Shukla, Commented Jun 20, 2022 at 10:18

broot · Accepted Answer · 2022-06-20 10:20:39Z

2

Equivalent of the above Python code in Kotlin is:

val mylist = listOf(1, 2)
val items = mylist.map { it * 2 }

If you need to assign resulting doubled values to first and second, then do it exactly as you did:

val (first, second) = mylist.map { it * 2 }

You need to be sure myList contains at least 2 items.

edited Jun 20, 2022 at 10:20

answered Jun 20, 2022 at 9:48

broot

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3 Comments

broot Over a year ago

I'm not sure about your example Kotlin code. It seems unrelated to what you do in Python.

Kaita John Over a year ago

I have edited my question to address this concern

broot Over a year ago

I'm still not exactly sure what you mean. You first speak about creating an array/list from another list and then you jump into unpacking/destructuring into first/second, which is pretty unrelated thing. If you just wanted to use both of these features at the same time then see my updated answer.

Iqbal Hussain · Accepted Answer · 2022-06-20 09:53:28Z

2

Try this out:

// === KOTLIN

var mylist = listOf(1, 2)

            
val result = mylist.map { it * 2 }

println(result)
// output: [ 2,4 ]

edited Jun 20, 2022 at 9:53

answered Jun 20, 2022 at 9:52

Iqbal Hussain

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