Effective way to get random item in Scala?

Question

What is an effective way to get a random item from a collection in Scala? There is a related question there, but, like one of the comments, “the question does not ask for any need for efficiency.”

Answer 1

A custom collection may not be available for a fixed time. Therefore, you need a special collection with the desired property. For example - Vector or Array . See Collection Performance Specifications for others.

Answer 2

Use a collection using the size () and get () methods with constant time.

Answer 3

If you need a random order of all elements of the collection, then Random.shuffle is what you need. (It is better to convert the original collection into an array to avoid direct and inverse conversion.)

Answer 4

 util.Random.shuffle(List.range(1,100)) take 3