ok i found the answer
Create three new datastores from the files in imds. The first datastore imds60 contains the first 60% of files with the demos label and the first 60% of files with the imagesci label. The second datastore imds10 contains the next 10% of files from each label. The third datastore imds30 contains the remaining 30% of files from each label. If the percentage applied to a label does not result in a whole number of files, splitEachLabel rounds down to the nearest whole number.
[imds60, imds10, imds30] = splitEachLabel(imds,0.6,0.1)