Simplest way to find the element that occurs the most in each column

Question

Suppose I have

data =
[[a, a, c],
 [b, c, c],
 [c, b, b],
 [b, a, c]]

I want to get a list containing the element that occurs the most in each

Answer 1

In statistics, what you want is called the mode. The scipy library (http://www.scipy.org/) has a mode function, in scipy.stats.

In [32]: import numpy as np

In [33]: from scipy.stats import mode

In [34]: data = np.random.randint(1,6, size=(6,8))

In [35]: data
Out[35]: 
array([[2, 1, 5, 5, 3, 3, 1, 4],
       [5, 3, 2, 2, 5, 2, 5, 3],
       [2, 2, 5, 3, 3, 2, 1, 1],
       [2, 4, 1, 5, 4, 4, 4, 5],
       [4, 4, 5, 5, 2, 4, 4, 4],
       [2, 4, 1, 1, 3, 3, 1, 3]])

In [36]: val, count = mode(data, axis=0)

In [37]: val
Out[37]: array([[ 2.,  4.,  5.,  5.,  3.,  2.,  1.,  3.]])

In [38]: count
Out[38]: array([[ 4.,  3.,  3.,  3.,  3.,  2.,  3.,  2.]])