Scala ListBuffer (or equivalent) shuffle

arrays list scala shuffle
rdlu picture rdlu · Jun 14, 2012 · Viewed 8.7k times · Source

Is there a simple shuffle function for Scala lists?

If not, whats the simplest way to implement?

I have a lot of these things to do all over the code, so the simpler the call, the best it is

An example in Ruby

a = [ 1, 2, 3 ]           #=> [1, 2, 3]
a.shuffle                 #=> [2, 3, 1] returns new array shuffled

Thanks in advance :)

Answer

Tomasz Nurkiewicz picture Tomasz Nurkiewicz · Jun 14, 2012

In Scala you can use scala.util.Random:

util.Random.shuffle((1 to 10).toSeq)
//Vector(9, 6, 8, 7, 10, 1, 2, 5, 3, 4)

util.Random.shuffle(List('A', 'B', 'C', 'D', 'E', 'F'))
//List(B, D, A, E, C, F)

Your results may vary...

Related questions

Difference between Array and List in scala

In what cases I should use Array(Buffer) and List(Buffer). Only one difference that I know is that arrays are nonvariant and lists are covariant. But what about performance and some other characteristics?

Read More
How to randomly sample from a Scala list or array?

I want to randomly sample from a Scala list or array (not an RDD), the sample size can be much longer than the length of the list or array, how can I do this efficiently? Because the sample size can …

Read More
Why are Arrays invariant, but Lists covariant?

E.g. why does val list:List[Any] = List[Int](1,2,3) work, but val arr:Array[Any] = Array[Int](1,2,3) fails (because arrays are invariant). What is the desired effect behind this design decision?

Read More