How to create and populate Scala Vectors (syntax, examples)

This page contains a collection of examples that show how to create and populate instances of the Scala Vector class.

Create a new Vector with initial elements

To create a new Vector with initial elements:

val nums = Vector(1, 2, 3)

val people = Vector(
    Person("Emily"),
    Person("Hannah"),
    Person("Mercedes")
)

When you need to be clear about what’s in the vector:

val x = Vector(1, 1.0, 1F)                   # Vector[Double] = Vector(1.0, 1.0, 1.0)
val x: Vector[Number] = Vector(1, 1.0, 1F)   # Vector[Number] = Vector(1, 1.0, 1.0)

trait Animal
case class Dog(name: String) extends Animal
case class Cat(name: String) extends Animal
val animalHouse: Vector[Animal] = Vector(    # Vector[Animal] = Vector(Dog(Rover), Cat(Felix))
    Dog("Rover"),
    Cat("Felix")
)

If you ever need to create an empty vector:

val nums = Vector[Int]()

Remember the construction syntax is just syntactic sugar for apply:

val nums = Vector(1, 2, 3)                   # Vector(1, 2, 3)
val nums = Vector.apply(1, 2, 3)             # Vector(1, 2, 3)

Create a new Vector by populating it

You can also create a new Vector that’s populated with initial elements using a Range:

# to, until
(1 to 5).toVector                   # Vector(1, 2, 3, 4, 5)
(1 until 5).toVector                # Vector(1, 2, 3, 4)

(1 to 10 by 2).toVector             # Vector(1, 3, 5, 7, 9)
(1 until 10 by 2).toVector          # Vector(1, 3, 5, 7, 9)
(1 to 10).by(2).toVector            # Vector(1, 3, 5, 7, 9)

('d' to 'h').toVector               # Vector(d, e, f, g, h)
('d' until 'h').toVector            # Vector(d, e, f, g)

('a' to 'f').by(2).toVector         # Vector(a, c, e)

# range method
Vector.range(1, 3)                  # Vector(1, 2)
Vector.range(1, 6, 2)               # Vector(1, 3, 5)

You can also use the fill and tabulate methods:

Vector.fill(3)("foo")               # Vector(foo, foo, foo)
Vector.tabulate(3)(n => n * n)      # Vector(0, 1, 4)
Vector.tabulate(4)(n => n * n)      # Vector(0, 1, 4, 9)

More information

I created this tutorial to show how to create and populate a Scala Vector, but for many more examples of how to work with Vector, see my Scala Vector class syntax and method examples tutorial. These same techniques also work with other Scala sequential collections classes, including Seq, List, Array, ArrayBuffer, and more.