Yes, as described here: https://kotlinlang.org/docs/reference/operator-overloading.html#assignments

how do I sort a collection by several properties but preserving the sort as i go

How do I sort ArrayList<Something> instead of theArrayList.sortBy{ it.foo} to avoid ConcurrentModificationException? CopyOnWriteArrayList?

If I have a class called

Colour(val red:Double, val green: Double, val Blue: Double)

what's the best way of defining some pre-defined colours, e.g. White being

Colour(1.0,1.0,1.0)

?

Probably the companion object:

class Colour(...) {
    companion object {
        val White = Colour (1.0, 1.0, 1.0)
        ....
    }
}

Used like

Colour.White

.

Hi guys, I want know if there is a document about the Kotlin’s project structure and what the projects do? thanks

If have a string and a number of character ranges and I want to replace each range with inside the string with a different one which doesn't have the same length. So, e.g. if I have "Carla and Bob went to school" and I want to replace the ranges of the names with e.g.

<name>Carla</name>

to finally get "<name>Carla</name> and <name>Bob</name> went to school". Is there an easy way in Kotlin to achieve this without tracking the lengths that I have already inserted?

Hi guys, I have a question regarding properties vs parameters in Kotlin. I use KDoc and have something like this:

/**
 * @property name ...
 */
class Person(private val name: String)

KDoc doesn't generate this. Only if I change property to param. Reading the linked SO thread it appears to actually be a property though. Can someone clarify please? https://stackoverflow.com/questions/45032436/what-is-the-difference-between-properties-and-parameters-in-kotlin

Moreover, if I make the fields non-nullable like this:

data class GreetingDto(
  val greeting: String,
  val name: String
)

then I get another error:

groovy.lang.GroovyRuntimeException: Could not find matching constructor for: app.greeting.GreetingDto(LinkedHashMap)

Suppose I have a kotlin interface with

var background: Drawable

and I want to create a Kotlin class implementing this interface and extending a java class that already defines

setBackground(Drawable)

and

Drawable getBackground()

. In Java, I don't need to do anything because the new subclass automatically implements these interface methods. In Kotlin, I get a compile error that the new subclass does not implement those interface methods. How to achieve this?

Is it possible to write a Kotlin extension function that uses an autowired Spring bean?

Where is the best place to report compile errors and get answers instantly?

Hello. Is there a book or resource people would recommend for learning kotlin for more server programming than android?

lucky

maybe worth knowing, I am on kotlin

1.3.21

and the base classes are from spring (maybe I can post in spring channel as well, but this seems more generally related to kotlin, spring is relevant only because I have no influence on how

enhance

is called, it has to accept `null`s)

Hi, why does not work this?

val pair = Pair(1,"xxx")
map.put(*pair)

Hi ! I'm just a Kotlin begginner (and Already addicted), Do you know if there's projects to participate in order to improve my skills ?

Hi everyone - is Anko a given for most android projects? I’m a beginner and don’t like being too abstracted from what’s going on. But if it’s part of the canon for android development then I think it would be fine to use.

Hello! I have a stream of items much like this:

items.stream().filter { it.someStuff.equals(search) }.findFirst().orElseThrow( *insert exception* )

I tried to put UnsupportedOperationException() but get problem with ExceptionSupplier. How should I do this?

Hi all, just get started with Kotlin. Have started my first super simple Kotlin Android app and looking for simplest way can send tweets to twitter from it. Google search hasn't helped so far, so does anyone know a good place to get some good info on doing this? cheers

i want to filter the list

Currently it's implemented as

public inline fun <K, V> MutableMap<K, V>.getOrPut(key: K, defaultValue: () -> V): V {
    val value = get(key)
    return if (value == null) {
        val answer = defaultValue()
        put(key, answer)
        answer
    } else {
        value
    }
}

but it seems to me (based on the kdoc) that is should be more like

public inline fun <K, V> MutableMap<K, V>.getOrPut(key: K, defaultValue: () -> V): V {
    return if (contains(key)) {
        getValue(key)
    } else {
        val answer = defaultValue()
        put(key, answer)
        answer
    }
}

I want to filter the list for carMakes that have a constraint on the

name

field, then reconstruct this sortedmap agian

how can I do a sealed class that contains a data class and a String (that's for a Json file where I can have either of these two)

.iml files are getting really messed up in our Kotlin IntelliJ projects, any advice on that?

Sure, that's better, thanks. Interesting that

("a".."z").map{ it }

doesn't work (compiler error), can't map a String range.

❓ What's the cleanest way to test if all elements in a list are distinct? The best I could come up with was

list.size == list.distinct().size

, which is efficient, but ugly

what means

kotlin.jvm.JvmSynthetic

?

for example here