Mask an array where less than a given value.
This function is a shortcut to masked_where, with condition = (x < value).
See also
Examples
>>> import numpy.ma as ma
>>> a = np.arange(4)
>>> a
array([0, 1, 2, 3])
>>> ma.masked_less(a, 2)
masked_array(data = [-- -- 2 3],
mask = [ True True False False],
fill_value=999999)