I have used it like this:
for (int i = 0; i < result.Count; i++)
{
object[] atom = result[i];
atom[3] = atom[3] ?? 0;
atom[4] = atom[4] != null ? "Test" : string.Empty;
atom[5] = atom[5] ?? "";
atom[6] = atom[6] ?? "";
atom[7] = atom[7] ?? "";
atom[8] = atom[8] ?? "";
atom[9] = atom[9] ?? "";
atom[10] = atom[10] ?? "";
atom[12] = atom[12] ?? false;
}