kotlinlang #getting-started

Also related to AoC earlier - does Kotlin have any circular linked list data type or would I just use any Java implementation that I've previously had? My instincts tell me no since most Kotlin collections are based upon the Java ones.

dierre

12/02/2017, 5:55 PM

mmm..how do I access to the next element using fold? the operation would be: if next is bigger than the current value

Diaa Jad

12/02/2017, 11:46 PM

I might be overlooking an obvious solution, but how to convert a

char

to an

Int

var.toInt()

returns the ASCII value of the character.

Shawn

12/05/2017, 7:51 PM

if you want the resulting type to be

Map<String, List<String>>

you’re probably going to have to do some casting

katien

12/05/2017, 8:12 PM

thank you guys for explaining all that 🙂 managed to put it all together and get it working with mapValues

Copy code

errors.mapValues { (_, v) ->
                     when (v) {
                        is String -> listOf(v)
                        is List<*> -> v as List<String>
                        else -> listOf(v.toString())
                    }
                }

👍 1

Regan Russell

12/05/2017, 9:33 PM

I want to do something like this: mylist.sort { it.popular or not } and then mylist.sort { it.name ascending } in the one list. I want the popular at the top and the rest sorted by name

spragg

12/06/2017, 2:45 AM

This blog might help https://proandroiddev.com/understanding-generics-and-variance-in-kotlin-714c14564c47

👍 1

PN10

12/06/2017, 6:47 AM

Hi folks, Suggest me MOOC for kotlin looking for some really good beginner stuff to start with kotlin for Android??Free stuff only??

Jakub Kornatowski

12/06/2017, 1:26 PM

Hi all guys! Looking for good tutorial for Kotlin + Spring Boot (Notice that I don’t know Spring)

karelpeeters

12/07/2017, 5:33 PM

thingy?.let { Foo(it) } ?: Foo(defaultThingy, additionalParam)

kastork

12/07/2017, 8:53 PM

From the guide I know that

lateinit

vars cannot be primitive types. If you're trying to create a bean-compliant class, how do you designate an

Integer

Double

type? If you make the property type

Int

you get the error that primitive types can't be

lateinit

, if you give it the type

Integer

you get the warning that you shouldn't use

Integers

but should use

Int

.. And for

Double

there doesn't even appear to be a way to say you want the Object

Double

and not a primitive

double

shamrock_frost

12/08/2017, 12:10 AM

What's the most idiomatic way to match on the type of multiple expressions? e.g.

Copy code

class A
class B : A
class C : A

class X
class Y : X
class Z : X

fun example(a : A, x : X) = when(a, x) {
  is B, is Y -> "B and Y"
  is C, is Z -> "C and Z"
  else -> "Not an interesting case"
}

adam-mcneilly

12/08/2017, 4:55 PM

God I knew I would be mad I remember it being an obvious name. Thank you.

dierre

12/09/2017, 10:21 AM

Hi, I'm experimenting with kotlin multiproject. There is something that it's not clear to me. My goal is to port a node js project, a simple one ( https://github.com/invasionofsmallcubes/deals-bot ). The idea is to begin with the porting, isolate common code and repository interfaces on the common project, and then create the jvm version using

TelegramBots

(https://github.com/rubenlagus/TelegramBots). The goal is to have two running bots, the js and the kotlin one with one common business logic. I hope it's all clear up to this point. Now the question: for testing, on the node js I used jest + nock. Now I would see, as an advantage, the fact that I can use a java/kotlin mock library (I want to mock the telegram API) inside kotlin test. Of course the library that I will use to implement the bot is a javascript library. So, basically, can I implement my telegram bot in kotlin, using telegram bot js library, and testing it with, as an example, OkHttp MockWebServer?

techie01

12/11/2017, 11:49 AM

how to get the time in this format datetime.datetime(2015, 12, 5, 18, 17, 58, tzinfo=<UTC>)

danneu

12/11/2017, 9:51 PM

i mean what's a nice way for others to actually download it? perhaps github release zipballs

danneu

12/12/2017, 1:32 AM

that's the problem with an api like

ctx.write(Any)

e.g.

ctx.write(response)

in this case. type system can't help

karelpeeters

12/12/2017, 9:04 AM

Kotlin doesn't have a ternary operator, use

if(...) then ... else ...

😞 2

elye

12/13/2017, 12:58 AM

Could someone help check out this https://stackoverflow.com/questions/47783929/kotlin-nullibility-check-if-else-functional-approach-how. Thank you!!!

GauthierPLM

12/13/2017, 1:34 PM

Hi, how can I take elements between two index in a collection? For example, I have a list of 5 elements and I want to take the second to the fourth elements of this list.

melston

12/13/2017, 10:48 PM

I found Kotlin in Action (Manning) to be pretty good.

❤️ 3

lawlorslaw

12/14/2017, 6:34 PM

What is the recommended approach to a first Kotlin project? Start writing Kotlin code in an Android project, or convert an existing Android project written in Java to Kotlin?

danneu

12/15/2017, 4:45 AM

what's a good way to quickly bench competing implementations of a function? is there something robust but as simple as running each function in a loop + system.getCurrentMillis(), and then doing it a few times to warm up the jvm?

techie01

12/15/2017, 10:53 AM

i am from hyderabad can i get the kotlin hard copy book

asad.awadia

12/16/2017, 1:39 AM

Isnt it imported by default with the kotlin.collections package?

Tachyon

12/17/2017, 1:04 PM

well, I converted the whole project to kotlin

visakha

12/17/2017, 1:44 PM

i.e (abc){lambda} rather than (abc,{lambda})

rashadfl

12/17/2017, 7:14 PM

Just started this course and I'm uber new programming. Things were going well for me until section which deals with the terminal after stumbling my way through this section I finally have ran into a road block I can't over come these two issues... Can't start Git: C:\Program Files (x86)\Git\git-cmd.exe Probably the path to Git executable is not valid and this Invalid VCS root mappings The following directories are registered as VCS roots, but they are not: <Project> C:\Users....\Desktop\Test

🚓 3

dgngulcan

12/17/2017, 9:24 PM

I am to write an SDK and to decide to write with Kotlin or Java. Is there any comparison articles or some sort of guide about best practices on writing APIs in Kotlin that can be called from Java without ugliness? Thanks

KronicDeth

12/18/2017, 3:30 PM

Can I turn this into a property with a

private set

and custom

get

Copy code

java
  private ProjctSdksModel myModel
  public ProjectSdksModel getModel() {
    if (myModel == null) {
      myModel = new ProjectSdksModel();
      myModel.reset(null);
    }
    return myModel;

If I try

Copy code

kotlin
var model: ProjectSdksModel? = null
        get() {
            if (this.model == null) {

            }

            return this.model
        }
        private set

I get warning that

this.model

is or

model

is recursive and my google-fu is failing for how to refer to the current property inside the getter