fun main() {
    listOf(1, 2, 3)
        // Lambda, it is inferred argument, only used for single argument lambdas
        .filter { it % 2 == 0 }
        // Explicitly define args
        .map { value -> value * value }

    mapOf(1 to 2)
        // Automatic destructuring of mep entries
        .mapValues { (key, value) -> "$key $value" }
}

fun returnFromLambda(): List<Int> {
    return listOf(3, 0, 5)
        .flatMap {
            if (it == 0) return emptyList() // Returns from the function, will always return an empty list when 0
            listOf(it, it)
        }
}

fun returnFromLambda2(): List<Int> {
    return listOf(3, 0, 5)
        .flatMap {
            if (it == 0) return@flatMap emptyList() // Returns from the lambda
            listOf(it, it)
        }
}

fun returnFromLambda3(): List<Int> {
    return listOf(3, 0, 5)
        .flatMap l@{ // Define custom label
            if (it == 0) return@l emptyList() // Returns from the lambda
            listOf(it, it)
        }
}