Python program to find common elements in three lists using sets

Given three arrays, we have to find common elements in three sorted lists using sets.

Examples:

 Input: ar1 = [1, 5, 10, 20, 40 , 80] ar2 = [6, 7, 20, 80, 100] ar3 = [3, 4, 15, 20, 30, 70, 80, 120] Output: [80, 20] Input: ar1 = [1, 5 , 5] ar2 = [3, 4, 5, 5, 10] ar3 = [5, 5, 10, 20] Output: [5] 

Fit:
We have given three arrays, with the help of sets you can easily find the intersection of these arrays.

The intersection method simply ensures the intersection of both arrays on which you want to perform the intersection operation (or simply gives the common elements in both arrays). We will take three arrays and then select an intersection.

Below is the implementation of the above approach:

# Python3 program for finding common elements
# in three lists using sets

 

def IntersecOfSets (arr1, arr2, arr3):

# Convert arrays to sets

  s1 = set (arr1)

s2 = set (arr2)

  s3 = set (arr3)

 

# Calculates intersection

# sets to s1 and s2

set1 = s1.intersection (s2)  # [80, 20, 100]

 

# Calculates set intersection

# on set1 and s3

result_set = set1.inter section (s3)

 

# Converts the result set to a list

final_list = list (result_set)

print (final_list)

  
Driver code

if __ name__ = = `__main__` :

 

# Array items

arr1 = [ 1 , 5 , 10 , 20 , 40 , 80 , 100 ]

 

# Elements in Array2

  arr2 = [ 6 , 7 , 20 , 80 , 100 ]

 

# Elements in Array3

arr3 = [ 3 , 4 , 15 , 20 , 30 , 70 , 80 , 120 ]

 

# Function call

Inters ecOfSets (arr1, arr2, arr3)

Output:

 [80, 20]