Question

I’m new to scala, and what I’m learning is tuple.

I can define a tuple as following, and get the items:

val tuple = ("Mike", 40, "New York")
println("Name: " + tuple._1)
println("Age: " + tuple._2)
println("City: " + tuple._3)

My question is:

1. How to get the length of a tuple?
2. Is tuple mutable? Can I modify its items?
3. Is there any other useful operation we can do on a tuple?

Thanks in advance!

Answer 1

1] tuple.productArity

2] No.

3] Some interesting operations you can perform on tuples: (a short REPL session)

scala> val x = (3, "hello")
x: (Int, java.lang.String) = (3,hello)

scala> x.swap
res0: (java.lang.String, Int) = (hello,3)

scala> x.toString
res1: java.lang.String = (3,hello)

scala> val y = (3, "hello")
y: (Int, java.lang.String) = (3,hello)

scala> x == y
res2: Boolean = true

scala> x.productPrefix
res3: java.lang.String = Tuple2

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

scala> while(xi.hasNext) println(xi.next)
3
hello

See scaladocs of Tuple2, Tuple3 etc for more.