import h5py


srchdf = h5py.File("data/catalog-20210311-goodphot_lite.vaex.hdf5")
desthdf = h5py.File("sample.hdf5", "w")
columns_copy = desthdf.create_group("table/columns")
columns = srchdf["table"]["columns"]
for colName, col in list(columns.items()):
	new_col = columns_copy.create_group(colName)
	new_col.create_dataset("data", data=col["data"][:2000])
desthdf.close()