Python - Elements with K lists similar index value

Sometimes, while working with data, we can have a problem in which we need to get elements which are similar in K lists in particular index. This can have application in many domains such as day-day and other domains. Lets discuss certain ways in which this task can be performed.

Method #1 : Using zip() + loop
This is brute way in which this task can be performed. In this, we iterate the loop in zipped list and compare with elements in particular index for similarity.

# Python3 code to demonstrate  
# Elements with K lists similar index value 
# using zip() + loop 
  
# Initializing lists 
test_list1 = [1, 3, 5, 7] 
test_list2 = [1, 4, 8, 9] 
test_list3 = [3, 7, 5, 10] 
  
# printing original lists 
print("The original list 1 is : " + str(test_list1)) 
print("The original list 2 is : " + str(test_list2)) 
print("The original list 3 is : " + str(test_list3)) 
  
# Initializing K  
K = 2
  
# Elements with K lists similar index value 
# using zip() + loop 
res = [] 
for a, b, c in zip(test_list1, test_list2, test_list3): 
    if a == b or b == c or c == a: 
        if a == b: 
            res.append(a) 
        elif b == c: 
            res.append(b) 
        elif c == a: 
            res.append(c) 
  
# printing result  
print ("The list after checking on 2 lists : " + str(res)) 

Output :

The original list 1 is : [1, 3, 5, 7]
The original list 2 is : [1, 4, 8, 9]
The original list 3 is : [3, 7, 5, 10]
The list after checking on 2 lists : [1, 5]

Method #2 : Using list comprehension + set() + count()
The combination of above methods can also be used to perform this task. In this, we check for count using count() and rest of functionalities are performed using list comprehension.

# Python3 code to demonstrate  
# Elements with K lists similar index value 
# using list comprehension + count() + set() 
  
# Initializing lists 
test_list1 = [1, 3, 5, 7] 
test_list2 = [1, 4, 8, 9] 
test_list3 = [3, 7, 5, 10] 
  
# printing original lists 
print("The original list 1 is : " + str(test_list1)) 
print("The original list 2 is : " + str(test_list2)) 
print("The original list 3 is : " + str(test_list3)) 
  
# Initializing K  
K = 2
  
# Elements with K lists similar index value 
# using list comprehension + count() + set() 
res = [ele for sub in zip(test_list1, test_list2, test_list3) for ele in set(sub) if sub.count(ele) > 1] 
  
# printing result  
print ("The list after checking on 2 lists : " + str(res)) 

Output :

The original list 1 is : [1, 3, 5, 7]
The original list 2 is : [1, 4, 8, 9]
The original list 3 is : [3, 7, 5, 10]
The list after checking on 2 lists : [1, 5]

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Python – Elements with K lists similar index value

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