title: How to split an image datastore for cross-validation in MATLAB?
body: <p>In MATLAB the method <code>splitEachLabel</code>of an <code>imageDatastore</code> object splits an image data store into proportions per category label. How can one split an image data store for training using cross-validation and using the <code>trainImageCategoryCalssifier</code> class? </p>
  
  <p>I.e. it's easy to split it in N partitions, but then some sort of <code>_mergeEachLabel_</code> functionality is needed to be able to train a classifier using cross-validation. </p>
  
  <p>Or is there another way of achieving that?</p>
  
  <p>Regards,
  Elena</p>