Array initializing in Scala

Question

I'm new to Scala ,just started learning it today.I would like to know how to initialize an array in Scala.

Example Java code

String[] arr = { "Hello", "World" };

What is the equivalent of the above code in Scala ?

Solution 1

scala> val arr = Array("Hello","World")
arr: Array[java.lang.String] = Array(Hello, World)

Solution 2

To initialize an array filled with zeros, you can use:

> Array.fill[Byte](5)(0)
Array(0, 0, 0, 0, 0)

This is equivalent to Java's new byte[5].

Solution 3

Can also do more dynamic inits with fill, e.g.

Array.fill(10){scala.util.Random.nextInt(5)} 

==>

Array[Int] = Array(0, 1, 0, 0, 3, 2, 4, 1, 4, 3)

Solution 4

Additional to Vasil's answer: If you have the values given as a Scala collection, you can write

val list = List(1,2,3,4,5)
val arr = Array[Int](list:_*)
println(arr.mkString)

But usually the toArray method is more handy:

val list = List(1,2,3,4,5)
val arr = list.toArray
println(arr.mkString)

Solution 5

If you know Array's length but you don't know its content, you can use

val length = 5
val temp = Array.ofDim[String](length)

If you want to have two dimensions array but you don't know its content, you can use

val row = 5
val column = 3
val temp = Array.ofDim[String](row, column)

Of course, you can change String to other type.

If you already know its content, you can use

val temp = Array("a", "b")

View more solutions

Comments

[Anderson Green]

This answer doesn't yet explain how to initialize multidimensional arrays in Scala (which is addressed here: stackoverflow.com/questions/13862568/…)

[cevaris]

Just FYI, List as an equivalent initializer List.fill(5)(0), accepts even functions. List.fill(5)(myFunc())