Reverse sort of Numpy array with NaN values

Question

I have a numpy array with some NaN values:

>>> a
array([  1.,  -1.,   nan,  0.,  nan], dtype=float32)

I can sort it in ascending or 'descending' order:

>>> numpy.sort(a)
array([ -1.,   0.,   1.,  nan,  nan], dtype=float32)
>>> numpy.sort(a)[::-1]
array([ nan,  nan,   1.,   0.,  -1.], dtype=float32)

However, what I want is descending order with NaN values at the end, like this:

>>> numpy.genuine_reverse_sort(a)
array([ 1.,   0.,   -1.,  nan,  nan], dtype=float32)

How could this be accomplished? I suspect that there is no special method for this.

Answer 1

What about negating the values twice:

>>> a = np.array([2., -1., nan,  0., nan])
>>> np.sort(a)
array([ -1.,   0.,   2.,  nan,  nan])
>>> -np.sort(-a)
array([  2.,   0.,  -1.,  nan,  nan])