How to make an ArrayBuffer of ArrayBuffer

Question

I want a two-dimensional array of ArrayBuffer

Something like this:

var myRowOfStrings = new ArrayBuffer[String]
val myArrayOfRows = new ArrayBuffer[ArrayBuffer] // To store many ArrayBuffer[String]

But the Scala compiler doesn't like the second declaration:

scala> val myArrayOfRows = new ArrayBuffer[ArrayBuffer]
<console>:8: error: class ArrayBuffer takes type parameters
       val myArrayOfRows = new ArrayBuffer[ArrayBuffer]
                                       ^

Have I got the syntax wrong?

Or is an ArrayBuffer of ArrayBuffer not possible?

Kyle · Accepted Answer · 2012-08-15 03:51:23Z

11

ArrayBuffer objects require a type. It says so in the error message.

You need to tell the compiler what type of ArrayBuffer you want.

scala> import scala.collection.mutable.ArrayBuffer
import scala.collection.mutable.ArrayBuffer

scala> val myArrayOfRows = new ArrayBuffer[ArrayBuffer[String]]
myArrayOfRows: scala.collection.mutable.ArrayBuffer[scala.collection.mutable.ArrayBuffer[String]] = ArrayBuffer()

Consider doing this if its easier.

type Row = ArrayBuffer[String]
var myRowOfStrings = new Row
val myArrayOfRows = new ArrayBuffer[Row]

edited Aug 15, 2012 at 3:51

answered Aug 15, 2012 at 3:35

Kyle

22.3k2 gold badges63 silver badges63 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

kevin_theinfinityfund · Accepted Answer · 2020-12-15 21:18:28Z

0

Import ArrayBuffer before applying it:

import scala.collection.mutable.ArrayBuffer
var e = ArrayBuffer("a", "b", "c")

scala> e: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(a, b, c)

answered Dec 15, 2020 at 21:18

kevin_theinfinityfund

2,20519 silver badges19 bronze badges

Collectives™ on Stack Overflow

How to make an ArrayBuffer of ArrayBuffer

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related