function Data = GetGroupingVar(data,varargin) if nargin == 1 for i=1:length(data) Data(i,1)=i; end elseif nargin == 2 if ischar(varargin{1}) for i=1:length(data) Data{i,1} = varargin{1}; end else n=varargin{1}; Data = n*ones(length(data),1); end end