Scala @ operator

by

It enables one to bind a matched pattern to a variable. Consider the following, for instance:

val o: Option[Int] = Some(2)

You can easily extract the content:

o match {
  case Some(x) => println(x)
  case None =>
}

But what if you wanted not the content of Some, but the option itself? That would be accomplished with this:

o match {
  case x @ Some(_) => println(x)
  case None =>
}

Note that @ can be used at any level, not just at the top level of the matching.

More Related Contents:

  1. What do all of Scala’s symbolic operators mean?
  2. Valid identifier characters in Scala
  3. What good are right-associative methods in Scala?
  4. What’s the difference between => , ()=>, and Unit=>
  5. What is the advantage of using abstract classes instead of traits?
  6. Split 1 column into 3 columns in spark scala
  7. Linearization order in Scala
  8. private[this] vs private
  9. By-name parameter vs anonymous function
  10. Is there a way to control which implicit conversion will be the default used?
  11. how to filter out a null value from spark dataframe
  12. How to create a Source that can receive elements later via a method call?
  13. java.lang.NoSuchMethodError: scala.Predef$.refArrayOps
  14. Why are scala functions limited to 22 parameters?
  15. Method Override with Scala 3 Macros
  16. Replace missing values with mean – Spark Dataframe
  17. How to calculate the size of dataframe in bytes in Spark?
  18. Why does partition parameter of SparkContext.textFile not take effect?
  19. Can I zip more than two lists together in Scala?
  20. Usages of Null / Nothing / Unit in Scala
  21. Cross product in Scala
  22. Spark-Monotonically increasing id not working as expected in dataframe?
  23. Reading in multiple files compressed in tar.gz archive into Spark [duplicate]
  24. What is the fastest way to write Fibonacci function in Scala?
  25. How to wait for several Futures?
  26. How do you define a local var/val in the primary constructor in Scala?
  27. Scala 2.10 reflection, how do I extract the field values from a case class, i.e. field list from case class
  28. assembly-merge-strategy issues using sbt-assembly
  29. How to create a Dataset of Maps?
  30. Spark ML VectorAssembler returns strange output

Leave a Comment