Count only if empty

Syntax: BIN\EMPTY x xbin xcount
BIN\EMPTY\EDGES x xbin xcount

The \EMPTY qualifier means that an event is counted in a bin only if that bin is empty. So only the first event encountered for each bin will be counted in that bin. \EMPTY can be used with \WEIGHTS and \EDGES, but not with \AVERAGE.

  Average
  Edge defined bins