Canonical way for empty Array in Scala?
ScalaScala Problem Overview
What is the canonical way to get an empty array in Scala? new Array[String](0) is too verbose.
Scala Solutions
Solution 1 - Scala
Array[String]()
You can leave out the [String] part if it can be inferred (e.g. methodThatAlwaysTakesAStringArray( Array() )).
Solution 2 - Scala
val emptyArray = Array.empty[Type]
Solution 3 - Scala
Array() will be enough, most of the times. It will be of type Array[Nothing].
If you use implicit conversions, you might need to actually write Array[Nothing], due to Bug #3474:
def list[T](list: List[T]) = "foobar"
implicit def array2list[T](array: Array[T]) = array.toList
This will not work:
list(Array()) => error: polymorphic expression cannot be instantiated to expected type;
found : [T]Array[T]
required: List[?]
list(Array())
^
This will:
list(Array[Nothing]()) //Nothing ... any other type should work as well.
But this is only a weird corner case of implicits. It's is quite possible that this problem will disappear in the future.
Solution 4 - Scala
If the array type is one of the primitives, you can use the shortcuts from scala.Array.
For example for a byte array it would be:
val arr = Array.emptyByteArray
This is useful when the type cannot be inferred and you want to remain less verbose.
Solution 5 - Scala
Late to the party, but I like the expresiveness of:
Array.empty[String]