public string GetModificationClassification(HashSet <string> labelModificationSet) { PeptideModificationState trueMods = GetTrueModifications(labelModificationSet); ushort[] x = trueMods.GetModifications(); int index = -1; int count = 0; for (int i = 0; i < x.Length; i++) { if (x[i] != ushort.MaxValue) { count++; index = i; } } if (count == 0) { return("unmodified"); } if (count > 1) { return("multiple"); } return("" + x[index] + ";" + sequence[index]); }