How to get a reference to a string in Scala and modify the original string by modifying this reference?

Question

As I understand, strings in Scala are value types:

var a = "hello"
var b = a
b = "hi"

-

println(a)   // hello
println(b)  // hi

I want a to point to b and make code above print

hi
hi

Is this possible?

The title of your question is confused. Modifying references is separate from modifying values. Furthermore, Scala uses Java's `String` and they are immutable. — Randall Schulz, Mar 24 '13 at 16:55

score 3 · Accepted Answer · answered Mar 24 '13 at 12:24

3

Warning: This is very bad functional style

Your a and b are strings. What you want is a reference to a string!

class StringRef(var s:String)  

val a = new StringRef("hello")
val b = a
b.s = "Hi"
println(a.s)   // Hi
println(b.s)   // Hi

answered Mar 24 '13 at 12:24

corny

score 2 · Answer 2 · edited May 23 '17 at 10:32

2

You can't do this because in Java/Scala everything is assigned-by-value. You can't assign a variable to directly reference another variable.

Instead you can assign both variables to contain the same reference value to a mutable object.

edited May 23 '17 at 10:32

Community

answered Mar 24 '13 at 12:29

Garrett Hall

2 Answers2