kotlinlang #getting-started

hello folks.... I want to start with Kotlin.. so I decided to install Android Studio3.1 ...in my linux box, so after a couple of workarounds, the most closer I'm to boot up android Studio I get is "Error: Could not find or load main class com.intellij.idea.Main".... some clue about where to look for ? thanks in advance , and sorry if its not the right channel

fred.deschenes

11/03/2017, 2:45 PM

you'd have to declare your interfaces like this :

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interface Wtf<out A, out B, out C : Ftw<A, B>>
interface Ftw<out A, out B>

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Nathan Desmet

11/03/2017, 2:53 PM

Is there a way to compile a kotlin class without including the kotlin.Metadata annotation, because its value still exposes class information after obfuscation. (The code i’m compiling will not be used as a library, and doesn’t use kotlin-reflect)

Sudhir Singh Khanger

11/03/2017, 3:41 PM

println("item at $index is ${items[index]}")

What is the role of curly and square brackets in the above example?

pastjean

11/03/2017, 3:44 PM

https://kotlinlang.org/docs/reference/basic-types.html#string-templates <- here the doc

cconstable

11/03/2017, 7:31 PM

👋 Hi all, new to Kotlin and I'm having trouble understanding why the

->

is used to specify return types in some cases but not others (e.g.

is used in

fun

). Is there a reason for this perceived inconsistency?

CodeCrazy99

11/04/2017, 4:05 AM

Nice to find a kotlin community though, I'm learning Java and found kotlin to be the latest so learning both now

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✌️ 1

kristofdho

11/05/2017, 2:45 PM

or actually

.pairwise()

, even better (also 1.2)

Slackbot

11/06/2017, 3:58 PM

This message was deleted.

Andreas Sinz

11/06/2017, 5:42 PM

@Jorrit the code is here https://github.com/Kotlin/kotlin-koans/blob/master/src/i_introduction/_1_Java_To_Kotlin_Converter/JavaCode1.java

adrik77

11/06/2017, 6:57 PM

something like this?

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val list1 = listOf("a", "b")
    val list2 = listOf(1,2,3)
    val cartesianProduct = list1.map { e1-> list2.map { e2-> e1 to e2 } }.flatten()

elaborate tissue

11/07/2017, 6:48 AM

so that it returns the flat mapped elements as well as the remaining > n elements

wineluis

11/08/2017, 10:41 AM

how can I set the type here to accept any class that implements LAObject?

var clazz: Class<LAObject>? = null

Sandm

11/08/2017, 8:52 PM

I have such string: [["9.00"],[],[],[],[]], how do I turn it into list or array?

jamie-purchase

11/09/2017, 7:38 PM

Hi everyone - sorry if i'm not posting in the right place, i'm new here Jamie, live in Galway, Ireland - been experimenting with Kotlin for a short while now loved Java for years and still use it alot but loving the less-verbose and sexier Kotlin syntax anyway, I have a question about casting a value from a java method to a HashMap and i've exhausted my google-fu 😕 calling

getAttribute("something")

on an instance of

com.sun.net.httpserver.HttpHandler

and I need to cast it to

HashMap<String, Any>

but i'm unfamiliar with how to do that

diegog

11/10/2017, 6:29 PM

@elect where you looking for something like that?

shodan45

11/10/2017, 8:39 PM

if I'm starting a new kotlin project in intellij, what "type" of project should I pick?

karelpeeters

11/10/2017, 9:18 PM

Are you sure you even needed it? I think it should work without one too.

karelpeeters

11/11/2017, 9:12 AM

Like this: https://kotlinlang.org/docs/reference/generics.html

scottc

11/13/2017, 2:09 AM

I know thanks 🙂 . The reason I'm using the online version is that I couldn't figure out how to run individual tests in IntelliJ

Ruckus

11/13/2017, 6:38 PM

@jamie-purchase I would recommend the official guide (https://edvin.gitbooks.io/tornadofx-guide/content/). If you have any questions, the #tornadofx channel is a great place to ask. @edvin also has a number of useful videos on his channel: https://www.youtube.com/user/MrEdvinsyse/videos

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amatos

11/14/2017, 1:44 AM

I have a question: if I have a

person

class that has

district

and district has a

region

and region has a

country

, how should

person

have the reference to district? atm I have it like:

var district:District?=null

elye

11/14/2017, 2:45 PM

https://medium.com/@elye.project/mastering-kotlin-standard-functions-run-with-let-also-and-apply-9cd334b0ef84

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kevin_abrioux

11/14/2017, 5:52 PM

Hi all, with java, i have this syntax

MainActivity.this

what is the equivalent in Kotlin ?

Trevor

11/14/2017, 8:13 PM

Yeah I just want the compiler to catch all my mistake for me, and this seemed like a real easy case for the compiler to check that for me

shamrock_frost

11/15/2017, 7:01 AM

Why doesn't this give me

null

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sealed class E {
    data class A(val string : String) : E()
    sealed class B : E() {
        data class C(val int : Int) : B()
    }
}

val x : MutableList<E> = mutableListOf(E.A("a"), E.B.C(1))
println(x as? MutableList<E.B>)

viliusk

11/15/2017, 1:30 PM

How do you do searches on 🤖 from EditText on your API? I’m trying to use Rx for that: https://kotlinlang.slack.com/archives/C0B8Y8BHC/p1510752244000312

holgerbrandl

11/16/2017, 1:28 PM

Hmm, I could use

let

, but I actually would like to use a non-extension function on my argument:

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(listOf(1,2)).let { (x, y) -> x+y} //works
somefun(listOf(1,2)) { (x, y) -> x+y}  //want that

Rafael Schneider

11/17/2017, 1:05 AM

I like to colaborate developing and translating some documentation to portuguese language. I'm braziliam... 😉

elect

11/17/2017, 9:21 AM

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val console = object { fun draw() }
fun a() = console.draw() // error draw unresolved