Scala tuple

Scala collections

And lists, tuples is immutable, but the list is different from a tuple can contain different types of elements.

Value tuple is contained by a single value in parentheses constitution. E.g:

val t = (1, 3.14, "Fred")  

Examples of the above three elements are defined in the tuple corresponding to the type are [Int, Double, java.lang.String].

In addition, we can also be defined using the above method:

val t = new Tuple3(1, 3.14, "Fred")

The actual tuple type depends on the type of its elements, such as (99, "w3big") is Tuple2 [Int, String]. ( 'U', 'r', "the", 1, 4, "me") is Tuple6 [Char, Char, String, Int, Int, String].

Currently the maximum tuple length Scala support is 22. For greater lengths you can use the collection or extension tuples.

Access tuple elements can be numeric index, as a tuple:

val t = (4,3,2,1)

We can use the first element t._1 access, t._2 access the second element, as follows:

object Test {
   def main(args: Array[String]) {
      val t = (4,3,2,1)

      val sum = t._1 + t._2 + t._3 + t._4

      println( "元素之和为: "  + sum )
   }
}

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
元素之和为: 10

Iterative tuple

You can useTuple.productIterator () method to iterate over all the elements of the output tuples:

object Test {
   def main(args: Array[String]) {
      val t = (4,3,2,1)
      
      t.productIterator.foreach{ i =>println("Value = " + i )}
   }
}

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
Value = 4
Value = 3
Value = 2
Value = 1

Tuple into a string

You can useTuple.toString () method combines all the elements of the tuple into a string, examples are as follows:

object Test {
   def main(args: Array[String]) {
      val t = new Tuple3(1, "hello", Console)
      
      println("连接后的字符串为: " + t.toString() )
   }
}

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
连接后的字符串为: (1,hello,scala.Console$@4dd8dc3)

Switching element

You can use the method toTuple.swap exchange element of the tuple.The following examples:

object Test {
   def main(args: Array[String]) {
      val t = new Tuple2("www.google.com", "www.w3big.com")
      
      println("交换后的元组: " + t.swap )
   }
}

Implementation of the above code, the output is:

$ scalac Test.scala 
$ scala Test
交换后的元组: (www.w3big.com,www.google.com)

Scala collections