numpy.ma.MaskedArray.cumsum#

method

ma.MaskedArray.cumsum(axis=None, dtype=None, out=None)[source]#

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

>>> 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)