import glob import h5py for fpath in glob.glob('modelnet_c/*.h5'): f = h5py.File(fpath) data = f['data'][:].astype('float32') label = f['label'][:].astype('int64') f.close() f = h5py.File(fpath, 'w') f.create_dataset('data', data=data[:100]) f.create_dataset('label', data=label[:100]) f.close()