Why can't I iterate over (Int, Int, Int) with Map?

Question

Possible Duplicate:
Use 'map' and stuff on Scala Tuples?

Why cannot I iterate over this construct (I am not sure how to call it, since Scala just calls it (Int, Int, Int))?

val list = (1,2,3)
list.map{println _}

The code above produces the following error:

<console>:9: error: value map is not a member of (Int, Int, Int)
(1,2,3).map{println _}

score 5 · Answer 1 · answered May 07 '12 at 15:25

You can use .productIterator or .productElements for such things:

t.productElements.toList.map(println)

I've used toList to strict operation, cause productIterator returns Iterator which is lazy.

Tip: it is recommended to use .foreach for functions without result (those that produce side effects, just like println do)

t.productElements.toList.foreach(println)

score 4 · Answer 2 · edited May 23 '17 at 12:04

4

I got it.

It's called a "tuple", and it's already answered here.

edited May 23 '17 at 12:04

Community

answered May 07 '12 at 15:15

Karel Bílek

1

I added an answer to that question with a pointer to [shapeless](https://github.com/milessabin/shapeless) which might be useful. – Miles Sabin May 07 '12 at 18:59

score 3 · Answer 3 · edited May 07 '12 at 20:23

3

Based on on the name of your value list, it seems like you meant to use a List instead of a Tuple. Try this to create a List which defines map:

List(1,2,3).map{println _}

edited May 07 '12 at 20:23

drstevens

answered May 07 '12 at 15:16

ie.

1

could you please define the minus? – ie. May 07 '12 at 15:26
1

That was me, sorry about late reasoning. I've downvoted, cause *use another type/collection* is not appropriate general solution, IMO. You may have a tuple given by API (e.g. returned from function), or some other restriction, when you just can't write List(...) instead of (...) ) – om-nom-nom May 07 '12 at 17:31
1

+1 - It is very possible based on the value name `list` that in the original question, that a List was intended instead of a Tuple. Because of this, I feel that this is a valid answer. I edited to make it more clear what @ie is answering. The original question should be edited as well. – drstevens May 07 '12 at 19:15

3 Answers3