how to create a tuple whose size is not known in advance

Question

I want to create a tuple of size n, where n is an arbitrary integer (that is less than or equal to maximum tuple size). For example, with below data

val n = 3 //or 4 or 4 etc ; 
val y = 15
val z = 10
val e = 11

I am looking for a method like below

val x = genTuple(n,y,z,e)

that would return the following tuple

(15, 10, 11)

so how can create tuple of size n where the n can vary?

Tuples are immutable. You get what you construct, and that value never changes. There is no "populate"-phase. — Andrey Tyukin, Jun 06 '18 at 22:06
Hi Andrey, I know Tuples are immutable and get what you construct. But my value of n depends on user input. so how can I create a tuple and then populate the values that is passed in. — mike, Jun 06 '18 at 22:28
Then why do you want to use tuples for something they can't do? Why don't you just use `List.fill(n){value}` or something like that? — Andrey Tyukin, Jun 06 '18 at 22:32
A tuple's type is the combination of the types of its elements: `(Char,String)` or `(Int,Int,Int)` or `(Boolean,Float)` or ... If a tuple has no elements then it has no type and it's not a tuple. Empty parentheses `()`, which looks like an empty tuple, is the value expression of type `Unit` (the only value of that type). — jwvh, Jun 06 '18 at 22:35
Im using a tuple because i did not get to learning about list. So to understand you better can't use Tuples like this in scala??? — mike, Jun 06 '18 at 22:45
If a method can return a tuple of various sizes then the actual return type is not `Tuple` but rather `Product with Serializable` instead. Bad news. You don't want to go there. — jwvh, Jun 06 '18 at 22:53
I suggest to read an introduction to Scala that *at least* mentions `List`s. — Andrey Tyukin, Jun 06 '18 at 23:07

score -2 · Answer 1 · edited Jun 07 '18 at 16:33

-2

To populate the tuple, create an iterator on a tuple and then use it.

To populate your example: val x = (15,10,11) then run the following expressions @ Scala REPLS

scala> val xiterator = x.productIterator
xiterator: Iterator[Any] = non-empty iterator

scala> for(element <- xiterator) println(element)
15
10
11

Your tuple may vary in size, this will work.

edited Jun 07 '18 at 16:33

jwvh

answered Jun 07 '18 at 06:26

Omprakash

This doesn't populate a tuple. It prints out the contents of an already populated tuple. – jwvh Jun 07 '18 at 06:50
It's available @ https://stackoverflow.com/questions/11305290/is-there-way-to-create-tuple-from-listwithout-codegeneration – Omprakash Jun 07 '18 at 12:00
Yes, that link tries to answer the same question asked here. Your answer does not. You'll note that none of the answers offered will result in a _true_ mixed-type tuple. It can't easily be done and it's not a good idea. – jwvh Jun 07 '18 at 16:40

1 Answers1