Identify the observations that are in the training set of a cvpartition object for holdout validation.

Partition 10 observations for holdout validation. Select approximately 30% of the observations to be in the test (holdout) set.

rng('default') % For reproducibility
c = cvpartition(10,'Holdout',0.30)

c = 
Hold-out cross validation partition
   NumObservations: 10
       NumTestSets: 1
         TrainSize: 7
          TestSize: 3

Identify the training set observations. Observations that correspond to 1s are in the training set.

set = training(c)

set = 10x1 logical array

   1
   1
   1
   0
   1
   1
   1
   1
   0
   0

Visualize the results. All observations except the fourth, ninth, and tenth are in the training set.

h = heatmap(double(set),'ColorbarVisible','off');
sorty(h,'1','ascend')
ylabel('Observation')
title('Training Set Observations')

Identify the observations that are in the training sets of a cvpartition object for 3-fold cross-validation.

Partition 10 observations for 3-fold cross-validation. Notice that c contains three repetitions of training and test data.

rng('default') % For reproducibility
c = cvpartition(10,'KFold',3)

c = 
K-fold cross validation partition
   NumObservations: 10
       NumTestSets: 3
         TrainSize: 7  6  7
          TestSize: 3  4  3

Identify the training set observations for each repetition of training and test data. Observations that correspond to 1s are in the corresponding training set.

set1 = training(c,1)

set1 = 10x1 logical array

   0
   0
   1
   1
   1
   1
   1
   1
   0
   1

set2 = training(c,2);
set3 = training(c,3);

Visualize the results. All observations except the first, second, and ninth are in the first training set. All observations except the third, sixth, eighth, and tenth are in the second training set. All observations except the fourth, fifth, and seventh are in the third training set.

data = [set1,set2,set3];
h = heatmap(double(data),'ColorbarVisible','off');
sorty(h,{'1','2','3'},'ascend')
xlabel('Repetition')
ylabel('Observation')
title('Training Set Observations')