How to get a Random Object using Linq

Question

I am trying to get a random object within linq. Here is how I did.

//get all the answers
var Answers = q.Skip(1).Take(int.MaxValue);
//get the random number         


        

Answer 1

Late to the party but this is a high-up Google result. A succinct version could be:

var rnd = new Random();
var SelectedPost = q.OrderBy(x => rnd.Next()).Take(1);

It has the disadvantage that it'll apply a random number to all elements, but is compact and could easily be modified to take more than one random element.

Answer 2

I'm posting an answer because I don't have enough reputation to comment.

I like this answer:

SelectedPost = q.ElementAt(r.Next(1, Answers.Count()));

But ElementAt is zero based, surely starting at 1 and going to Answers.Count() you are going to end up potentially throwing an out of range, and you are never going to get the first entity.

Wouldn't

SelectedPost = q.ElementAt(r.Next(0, Answers.Count() - 1));

Be better?

Answer 3

Generic extension method based on the accepted answer (which doesn't always skip the first, and only enumerates the enumerable once):

 public static class EnumerableExtensions
    {
        public static T Random<T>(this IEnumerable<T> enumerable)
        {
            var r = new Random();
            var list = enumerable as IList<T> ?? enumerable.ToList();
            return list.ElementAt(r.Next(0, list.Count()));
        }
    }