[FIXED] NumPy - Find most common value in array, use largest value in case of a tie

Issue

There are so many questions around that deal with finding the most common value in an array, but all of them return the "first" element in case of a tie. I need the highest value from the list of tied elements, imagine something like this:

import numpy as np

my_array = [1, 1, 3, 3]
most_common = np.bincount(my_array).argmax()

This gives me 1, which is obviously not wrong, but I have a tied result here and I want to decide on my own what I want to do in that case. For my application, in case of such a tie I want the highest value from my_array, which is 3. How can I do that?

PS: need a Python 2.7 answer... sorry, but can't change that at the moment

Solution

You could apply argmax to the reversed output of bincount, and then adjust to take into account the reversal:

In [73]: x
Out[73]: array([3, 0, 2, 3, 1, 0, 1, 3, 2, 1, 1, 2, 1, 3, 3, 4])

In [74]: b = np.bincount(x)

In [75]: b
Out[75]: array([2, 5, 3, 5, 1])

In [76]: most_common = len(b) - 1 - b[::-1].argmax()

In [77]: most_common
Out[77]: 3

Answered By - Warren Weckesser