Get all elements that only occur once

Question

Using LINQ, can I get a list of all int elements that only occur once?

For instance

{1,2,4,8,6,3,4,8,8,2}

would become

Answer 1

Various Extension Methods you could use:

public static IEnumerable WhereUnique(this IEnumerable items)
{
    return items.GroupBy(x => x).Where(x => x.Count() ==1).Select(x => x.First());
}

possibly slightly more performant, depending on the distribution of your data:

public static IEnumerable WhereUnique(this IEnumerable items)
{
    return items.GroupBy(x => x).Where(x => !x.Skip(1).Any()).Select(x => x.First());
}

And WhereUniqueBy, which works similiar to MoreLinqs DistinctBy():

public static IEnumerable WhereUniqueBy(this IEnumerable items, Func func)
{
    return items.GroupBy(func).Where(x => x.Count() ==1).Select(x => x.First());
}