Kotlin fun() vs lambda is there difference?

问题

This question is about fun() vs a lambda block definitions and scopes.
i have tried define the expressions in two ways. Here is what i have tried:

  val myFunction = fun(){
    println("i am in a function")
    }

//but i also tried doing this:

    val myFunction = {
    println("i am in a lambda")
    }

my problem is i do not know if they are equivalent and same thing ?

回答1:

The differences are best described in https://kotlinlang.org/docs/reference/lambdas.html#anonymous-functions:

Anonymous functions allow you to specify return type, lambdas don't.
If you don't, return type inference works like for normal functions, and not like for lambdas.
As @dyukha said, the meaning of return is different:

A return statement without a label always returns from the function declared with the fun keyword. This means that a return inside a lambda expression will return from the enclosing function, whereas a return inside an anonymous function will return from the anonymous function itself.
There is no implicit it parameter, or destructuring.

Your specific cases will be equivalent, yes.

回答2:

See the reference: https://kotlinlang.org/docs/reference/lambdas.html

There are several ways to obtain an instance of a function type:

Using a code block within a function literal, in one of the forms:

a lambda expression: { a, b -> a + b },

an anonymous function: fun(s: String): Int { return s.toIntOrNull() ?: 0 }

Both give you a function object which can be used interchangeably

来源：https://stackoverflow.com/questions/58004914/kotlin-fun-vs-lambda-is-there-difference

标签

kotlin

lambda

anonymous-function