cross-validation for decision tree with matlab

4 次查看（过去 30 天）
chikilon
chikilon 2017-3-15
回答： Saurabh 2025-5-30
data_label={'Revenu','Propriete','Credit ','Classe'};
my_data={'Eleve','Superieur','Non','C1';
'Eleve','Superieur','Oui','C2';
'Eleve','Superieur','Non','C1';
'Eleve','Inferieur','Oui','C2';
'Moyen','Superieur','Non','C1';
'Moyen','Superieur','Oui','C2';
'Moyen','Inferieur','Non','C2';
'Moyen','Inferieur','Oui','C2';
'Faible','Inferieur','Non','C3';
'Faible','Inferieur','Oui','C3'};
and the code for cross-validation:
indices = crossvalind('Kfold',my_data(:,end),10);
cp = classperf(my_data(:,end));
for i = 1:10
test = (indices == i); train = ~test;
class = classify(my_data(test,:),my_data(train,:),my_data(train,:));
classperf(cp,class,test)
end
cp.ErrorRat
But i have this error:
Index exceeds matrix dimensions.
Error in test (line 23)
class = classify(my_data(tests,:),my_data(train,:),data_label(train,:));
Please helppppp !!!!

请先登录，再回答此问题。

回答（1 个）

Saurabh
Saurabh 2025-5-30
Hi @chikilon,
The error arises because 'classify' expects numerical input, but the data provided is in a cell array of strings.
Resolution Steps:
  • Convert Cell Array to Table:
data_label = {'Revenu','Propriete','Credit','Classe'};
my_data_table = cell2table(my_data, 'VariableNames', data_label);
  • Seprate Features and Labels
features = my_data_table(:, 1:end-1);
labels = my_data_table.Classe;
  • Convert Categorical Variables to Numeric:
features_array = table2array(features);
features_categorical = categorical(features_array);
features_numeric = dummyvar(features_categorical);
  • Perform 10-Fold Cross-Validation:
indices = crossvalind('Kfold', labels, 10);
cp = classperf(labels);
for i = 1:10
test = (indices == i);
train = ~test;
class = classify(features_numeric(test, :), features_numeric(train, :), labels(train));
classperf(cp, class, test);
end
error_rate = cp.ErrorRate;
This approach ensures compatibility with the 'classify' function by providing numerical inputs and properly formatted labels.
I hope this helps.

类别

在 Help Center 和 File Exchange 中查找有关 Get Started with MATLAB 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by