API.GetAuctionIDsMatching C# (CSharp) Method

    public static ulong[] GetAuctionIDsMatching(string String)
    {
        if (String[String.Length - 1] == ':')
                String = String.Remove(String.Length - 1);
            String = String.Replace(" ", "");
            string[] sp = String.Split(':');
            AuctionEntry[] d = _auctionData.ToArray();

            var a =
                from auction in d
                where auction.Compare(sp)
                select auction._id;

            return a.ToArray();
    }