>> [attrib1, attrib2, attrib3, attrib4, class] = textread('data\iris.data', '%f%f%f%f%s', 'delimiter', ',');
>> attrib = [attrib1'; attrib2'; attrib3'; attrib4']';
>> a = zeros(150, 1);
>> a(strcmp(class, 'Iris-setosa')) = 1;
>> a(strcmp(class, 'Iris-versicolor')) = 2;
>> a(strcmp(class, 'Iris-virginica')) = 3;
So far, attribute values are saved in attrib, and category values are saved in array a.