numpy.ma.MaskedArray.sum

method

ma.MaskedArray.sum(axis=None, dtype=None, out=None, keepdims=<no value>)[source]

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

Masked elements are set to 0 internally.

Refer to numpy.sum for full documentation.

See also

numpy.ndarray.sum

corresponding function for ndarrays

numpy.sum

equivalent function

Examples

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>>> import numpy as np
>>> x = np.ma.array([[1,2,3],[4,5,6],[7,8,9]], mask=[0] + [1,0]*4)
>>> x
masked_array(
  data=[[1, --, 3],
        [--, 5, --],
        [7, --, 9]],
  mask=[[False,  True, False],
        [ True, False,  True],
        [False,  True, False]],
  fill_value=999999)
>>> x.sum()
25
>>> x.sum(axis=1)
masked_array(data=[4, 5, 16],
             mask=[False, False, False],
       fill_value=999999)
>>> x.sum(axis=0)
masked_array(data=[8, 5, 12],
             mask=[False, False, False],
       fill_value=999999)
>>> print(type(x.sum(axis=0, dtype=np.int64)[0]))
<class 'numpy.int64'>

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