Quickest way to find the nth largest value in a numpy Matrix

Question

There are lots of solutions to do this for a single array, but what about a matrix, such as:

>>> k
array([[ 35,  48,  63],
       [ 60,  77,  96],
          


        

Answer 1

Using the 'unique' function is a very clean way to do it, but likely not the fastest:

k = array([[ 35,  48,  63],
           [ 60,  77,  96],
           [ 91, 112, 135]])
i = numpy.unique(k)[-2]

for the second largest