Sometimes, you need to pick up the $N$-th extremal values in a mutli-dimensional matrix.
Let's suppose it is represented as a
nd-array (here, I further suppose you are using the numpy library from the python language). Finding extremal values is easy with
argsort but this function operated on 1d vectors... Juggling around indices is sometimes not such an easy task, but luckily, we have the
Let's unwrap an easy solution combining these functions: