Constants of the numpy.ma module

In addition to the MaskedArray class, the numpy.ma module defines several constants.

numpy.ma. masked

The masked constant is a special case of MaskedArray, with a float datatype and a null shape. It is used to test whether a specific entry of a masked array is masked, or to mask one or several entries of a masked array:

>>> x = ma.array([1, 2, 3], mask=[0, 1, 0])
>>> x[1] is ma.masked
True
>>> x[-1] = ma.masked
>>> x
masked_array(data=[1, --, --],
             mask=[False,  True,  True],
       fill_value=999999)

numpy.ma. nomask

Value indicating that a masked array has no invalid entry. nomask is used internally to speed up computations when the mask is not needed. It is represented internally as np.False_.

numpy.ma. masked_print_options

String used in lieu of missing data when a masked array is printed. By default, this string is '--'.