Question

Ok I was in the process of getting an answer for another SO question, and I came up with the following function to get a distinct list of int’s:

    static List<Int32> Example(params List<Int32> lsts)
    {
        List<Int32> result = new List<int>();

        foreach (var lst in lsts)
        {
            result = result.Concat(lst).ToList();
        }

        return result.Distinct().OrderBy(c => c).ToList();
    }

When I look at var in VS2012, it says its of type Int32 not List<Int32>. Shown here:

Shouldn’t var be type List<Int32> ??

Answer 1

you are missing a [] at the end of the parameter type declaration:

//                                            v-- this is missing in your code
static List<Int32> Example(params List<Int32>[] lsts)
{
    List<Int32> result = new List<int>();

    foreach (var lst in lsts)
    {
        result = result.Concat(lst).ToList();
    }

    return result.Distinct().OrderBy(c => c).ToList();
}