Why "list.foreach(println(_ + "s"))" cannot work?

Asked Aug 23 '17 at 03:52

Active Aug 23 '17 at 05:57

Viewed 49 times

As the title describes, the code followed compiles successfully:

val list = List(1, 2, 3, 4)
list.foreach(println(_))

But if I replace the second line with

list.foreach(println(_ + "test"))

compilation shows error with

 missing parameter type for expanded function ((x$2) => x$2.$plus("ss"))
    list.foreach(println(_ + "ss"))

Again I replace the second with

list.foreach(number => println(number + "test"))

it works successfully again. I don't know why it happens. I guess maybe the _'s usage is wrong.

edited Aug 23 '17 at 05:57

asked Aug 23 '17 at 03:52

qitian

Please add the error logs here – VikasGoyal Aug 23 '17 at 03:56
@JohnJoe This is Scala code, not Java. – Andreas Aug 23 '17 at 03:58
you should be doing `list.foreach(x => println(x + "test"))` . I am looking for explanation myself as well though – Ramesh Maharjan Aug 23 '17 at 03:58

0 Answers0