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member reference in Kotlin(::)


By : user6099740
Date : August 27 2020, 05:00 PM
Any of those help Let's take a look what String::name actually is. It is a KProperty1. This interface implements (Student) -> String as well. So, we are actually dealing with a lambda which takes a Student as parameter and returns a String.
Now, what does the map function take? The map function takes a lambda which maps some type to another ((T) -> R), which means we can pass Student::name to it. Like for any function you put the parameters inside parentheses.
code :
list.map(Student::name) // variant 1
val lambda: (Student) -> String = { it.name }
list.map(lambda) // variant 2
list.map { it.name } // variant 3
list.map { Student::name }


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How to differentiate between a bound callable member reference and a function of the same type in kotlin?


By : Md Saad
Date : March 29 2020, 07:55 AM
I wish did fix the issue. One way to distinguish a lambda from a function reference within the type system is using the reflection interface KFunction, for example:
code :
fun <T> f(ref: T) where T : () -> Unit, T : KFunction<Unit> { /* ... */ }
fun g() { println("hello") }
f(::g) // OK

f { println("hello") } // Error: type parameter bound is not satisfied

error: expecting member declaration and error: unresolved reference: in kotlin


By : Alex Hudich
Date : March 29 2020, 07:55 AM
I wish this helpful for you In class Parent. , Try something like this:
code :
interface Humenable {
    fun Run()
}

class Student : Humenable {
    override fun Run() {
        println("Pass")
    }
}

fun main(args: Array<String>) {
    val student = Student()
    student.Run()
}

Kotlin a member reference to return the object itself


By : ysoserious
Date : March 29 2020, 07:55 AM
I hope this helps . There isn't a built in way as far as I know. Best you could do is write a function that does this once, and then refer to that when you need it, e.g.
code :
inline fun <T> identity(t: T) = t
"foo".let(::identity) // still "foo"

Member reference not working for maxBy in Kotlin immutable list


By : user3618092
Date : March 29 2020, 07:55 AM
wish helps you Here is my code which is not working: , TL;DR
people.maxBy(Person::age) would work (watch the brackets)
code :
public inline fun <T, R : Comparable<R>> Iterable<T>.maxBy(selector: (T) -> R): T? {

Kotlin map with function reference of a member function


By : user3688872
Date : March 29 2020, 07:55 AM
should help you out You can't do this
map requires transform: (T) -> R (≈ KFunction1) function
code :
class Parent {
    val child: Child = Child()

    fun foo() = child.doSomethingWithParent(this)
}

val l1 = list.map(Parent::foo)
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