ArrayBuffer, Part 1: Creating and Reading (Accessing)
Use the Scala ArrayBuffer type when you want:
- A mutable sequential collection type
- An indexed sequence, meaning that you can access any element in the sequence in constant or near-constant time
ArrayBuffer is your primary “go to” sequence for object-oriented programming (OOP).
Creating an ArrayBuffer
Examples of how to create an ArrayBuffer:
import scala.collection.mutable.ArrayBuffer
// empty
val fruits = ArrayBuffer[String]()
val ints = ArrayBuffer[Int]()
val people = ArrayBuffer[Person]()
// with elements
val fruits = ArrayBuffer("apple", "banana", "cherry")
val ints = ArrayBuffer(1, 2, 3)How to access (read) ArrayBuffer elements
Examples of how to access ArrayBuffer elements:
// access by index
fruits(0)
fruits(1)
// access in a `for` loop
for i <- ints do println(i)
// Updating elements with += and ++=:
val nums = ArrayBuffer(1, 2, 3) # ArrayBuffer(1, 2, 3)
nums += 4 # ArrayBuffer(1, 2, 3, 4)
nums += (5, 6) # ArrayBuffer(1, 2, 3, 4, 5, 6)
nums ++= List(7, 8) # ArrayBuffer(1, 2, 3, 4, 5, 6, 7, 8)More details
For more details and examples, see:
