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# numpy.ma.MaskedArray.cumsum

method

ma.MaskedArray.cumsum(axis=None, dtype=None, out=None)

  Return the cumulative sum of the array elements over the given axis.

  Masked values are set to 0 internally during the computation. However, their position is saved, and the result will be masked at the same locations.

  Refer to `numpy.cumsum` for full documentation.

  See also

  `numpy.ndarray.cumsum`

    corresponding function for ndarrays

  `numpy.cumsum`

    equivalent function

  Notes

  The mask is lost if out is not a valid `ma.MaskedArray` !

  Arithmetic is modular when using integer types, and no error is raised on overflow.

  Examples

      >>> import numpy as np
      >>> marr = np.ma.array(np.arange(10), mask=[0,0,0,1,1,1,0,0,0,0])
      >>> marr.cumsum()
      masked_array(data=[0, 1, 3, --, --, --, 9, 16, 24, 33],
                   mask=[False, False, False,  True,  True,  True, False, False,
                         False, False],
             fill_value=999999)