function resulting_labels = column_labels(q, labels, prefix)
% labels either a cell array of strings or a single string

columns = find_columns_by_label(q.labels, labels);
resulting_labels = q.labels(:,columns);

if nargin > 2
	for i=1:length(resulting_labels)
		resulting_labels{i} = [prefix resulting_labels{i}];
	end
end
