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  2. Python | Find the most common item in a 2D list

Python | Find the most common item in a 2D list

Examples :

  Input:  [[10, 20, 30], [20, 50, 10], [30, 50, 10]]  Output:  10  Input:  [[`geeks`,` wins`], [`techie`,` wins`]]  Output:  wins

Approach # 1 Using the max()

Pythonic`s first approach is to use max () Python method. First, we flatten the 2D list and then simply use the max () method to determine the maximum occuring element among all elements.

# Python3 program to find the majority
# common element in 2D list

 

def mostCommon (lst):

flatList = [el for sublist in lst for el in sublist]

retur n max (flatList, key = flatList.count)

 
# Driver code

lst = [[ 10 , 20 , 30 ], [ 20 , 50 , 10 ], [ 30 , 50 , 10 ]]

print (mostCommon (lst))

 

Output :

 10

There is another method to flatten the list like chain.from_iterable () which gives an alternative approach.

# Python3 program to find the majority
# general item in 2D list

from itertools import chain

 

def mostCommon (lst):

  flatList = list (chain.from_iterable (lst))

return max (flatList, key = flatList.count)

 
# Driver code

lst = [[[ 10 , 20 , 30 ], [ 20 , 50 , 10 ], [ 30 , 50 , 10 ]]

print (mostCommon (lst))

Output: 

 10

Approach # 2 Using most_common () from Collections

Most_common () is used to create a sequence of n most common input values. So we just flatten the list and find the most common element using the above method.

# Python3 program for finding the majority
# common item in 2D list

from itertools import chain

from collections import Counter

  

def mostCommon (lst):

flatList = chain.from_iterable (lst)

return Counter (flatList) .most_common ( 1 ) [ 0 ] [ 0 ]

 
# Driver code

lst = [[ 10 , 20 , 30 ], [ 20 , 50 , 10 ], [ 30 , 50 , 10 ]]

print (mostCommon (lst))

Exit :

 10