find row or column containing maximum value in numpy array

Question

How do I find the row or column which contains the array-wide maximum value in a 2d numpy array?

Answer 1

If you only need one or the other:

np.argmax(np.max(x, axis=1))

for the column, and

np.argmax(np.max(x, axis=0))

for the row.

Answer 2

You can use np.argmax along with np.unravel_index as in

x = np.random.random((5,5))
print np.unravel_index(np.argmax(x), x.shape)