www.gusucode.com > stats 源码程序 matlab案例代码 > stats/CreateNominalArraysExample.m
%% Create Nominal Arrays % This example shows how to create nominal arrays using |nominal|. %% Load sample data. % The variable |species| is a 150-by-1 cell array of character vectors containing % the species name for each observation. The unique species types are setosa, % versicolor, and virginica. load fisheriris unique(species) %% Create a nominal array. % Convert |species| to a nominal array using the categories occurring in % the data. speciesNom = nominal(species); class(speciesNom) %% Explore category levels. % The nominal array, |speciesNom|, has three levels corresponding to the % three unique species. The levels of a nominal array are the set of possible % values that its elements can take. getlevels(speciesNom) %% % A nominal array can have more levels than actually appear in the data. % For example, a nominal array named |AllSizes| might have levels |small|, % |medium|, and |large|, but you might only have observations that are |medium| % and |large| in your data. To see which levels of a nominal array are actually % present in the data, use |unique|, for instance, |unique(AllSizes)|. %% Explore category labels. % Each level has a label. By default, % |nominal| labels the category levels with the values occurring in the % data. For |speciesNom|, these labels are the species types. getlabels(speciesNom) %% Specify your own category labels. % You can specify your own labels for each category level. You can specify % labels when you create the nominal array. speciesNom2 = nominal(species,{'seto','vers','virg'}); getlabels(speciesNom2) %% % You can also change category labels on an existing nominal array using % |setlabels| %% Verify new category labels. % Verify that the new labels correspond to the original labels in |speciesNom|. isequal(speciesNom=='setosa',speciesNom2=='seto') %% % The logical value |1| indicates that the two labels, |'setosa'| and |'seto'|, % correspond to the same observations.