>>> from mindspore.dataset.transforms import Relational
>>> # Data before
>>> # | col |
>>> # +---------+
>>> # | [1,2,3] |
>>> # +---------+
>>> data = [[1, 2, 3]]
>>> numpy_slices_dataset = ds.NumpySlicesDataset(data, ["col"])
>>> numpy_slices_dataset = numpy_slices_dataset.map(operations=transforms.Mask(Relational.EQ, 2))
>>> # Data after
>>> # | col |
>>> # +--------------------+
>>> # | [False,True,False] |
>>> # +--------------------+
