Hello ! I would like to do something on a list, i think there is a function i don't know but i don't...

# announcements

[Louis]

Hello ! I would like to do something on a list, i think there is a function i don't know but i don't find it... Here is my code :

val stringList = somethingList.map {
   it.str
}

if (stringList.isNotEmpty()) {
   doSomethingWithMyList(stringList)
}

And i would like to do something like that

somethingList.map {
   it.str
}.unknownOperation { // here i need help
   doSomethingWithMyList(it)
}

[marstran]

also?

[marstran]

So:

somethingList.map { it.str }
             .also { doSomething(it) }

[Louis]

I have already seen i can use something like :

.also {
 if (isNotEmpty()) {
   doSomethingWithMyList(it)
  }
}

but i just would like to know if there is an operator or another way to do the apply and if not empty

[Louis]

I have created an extension function for doing it

fun <T> List<T>.doIfNotEmpty(action: (List<T>) -> Unit): List<T> = also {
        if (isNotEmpty()) {
            action(this)
        }
    }

And i use it like

somethingList.map {
  it.str
}.doIfNotEmpty { doSomethingWithMyList(it) }

I'm not sure it's the cleanest way to do

[gsala]

you can also use .takeIf { it.isNotEmpty() }?.let{ doSomething(it)}

[Louis]

Thanks, didn't know takeIf 👍