CART Algorithm with categorical predictor variables which consist of strings?

10 vues (au cours des 30 derniers jours)
Ines le 15 Mai 2012
I want to build a decision tree from categorical data, which consist of string names (in this case designating different chemical reaction types). Can I make Matlab to directly use these non-numerical data as predictor variable? Or do I have to convert the information in something numerical (which is in my case quite tedious...)
Thanks for your help (If you could maybe attach an example, that would be great! :)
PS: which function would you specifically recommend to use?

Réponses (1)

Tom Lane
Tom Lane le 15 Mai 2012
If you use or from the Statistics Toolbox, the input X matrix has to be numeric. However, the grp2idx function may make the conversion less tedious for you. Example:
load carsmall
X = [Weight grp2idx(Origin)];
a =,Cylinders,'cat',2);

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