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Python | Find most common element in each column in a 2D list
  • Last Updated : 24 Jun, 2019

Given a 2D list, write a Python program to find the most common element in each column of the 2D list.

Examples:

Input : [[1, 1, 3],
        [2, 3, 3],
        [3, 2, 2],
        [2, 1, 3]]
Output : [2, 1, 3]

Input : [['y', 'y'],
         ['y', 'x'],
         ['x', 'x']]
Output : ['y', 'x']

 

Method #1 : Using most_common() from collections module

most_common() return a list of the n most common elements and their counts from the most common to the least. Thus, we can easily find the most common elements in each column using list comprehension.






# Python3 program to find most common 
# element in each column in a 2D list
from collections import Counter
  
def mostCommon(lst):
          
    return [Counter(col).most_common(1)[0][0] for col in zip(*lst)]
          
# Driver code
lst = [[1, 1, 3],
       [2, 3, 3],
       [3, 2, 2],
       [2, 1, 3]]
print(mostCommon(lst))
Output:
[2, 1, 3]

 
Method #3 : Using mode() from statistics module




# Python3 program to find most common 
# element in each column in a 2D list
from scipy.stats import mode
import numpy as np
  
def mostCommon(lst):
      
    val, count = mode(lst, axis = 0)
    return val.ravel().tolist()
          
# Driver code
lst = [[1, 1, 3],
       [2, 3, 3],
       [3, 2, 2],
       [2, 1, 3]]
print(mostCommon(lst))
Output:
[2, 1, 3]

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