Python – Similar index elements frequency

Sometimes, while working with Python list, we can have a problem in which we need to check if one element has similar index occurrence in other list. This can have possible application in many domains. Lets discuss certain ways in which this task can be performed.

Method #1 : Using sum() + zip()
The combination of above functions can be used to perform this task. In this, we perform summation of elements that after zipping cross lists together match.

# Python3 code to demonstrate
# Similar index elements frequency
# using sum() + zip()

# Initializing lists
test_list1 = [1, 3, 5, 6, 8]
test_list2 = [4, 3, 6, 6, 10]

# printing original lists
print("The original list 1 is : " + str(test_list1))
print("The original list 2 is : " + str(test_list2))

# Similar index elements frequency
# using sum() + zip()
res = sum(x == y for x, y in zip(test_list1, test_list2))

# printing result
print ("Number of elements having similar index : " + str(res))

Output :

The original list 1 is : [1, 3, 5, 6, 8]
The original list 2 is : [4, 3, 6, 6, 10]
Number of elements having similar index : 2

Method #2 : Using list comprehension + enumerate()
The combination of above functionalities can be used to perform this task. In this, we iterate through each element in lists and increase the sum accordingly.

# Python3 code to demonstrate
# Similar index elements frequency
# using list comprehension + enumerate()

# Initializing lists
test_list1 = [1, 3, 5, 6, 8]
test_list2 = [4, 3, 6, 6, 10]

# printing original lists
print("The original list 1 is : " + str(test_list1))
print("The original list 2 is : " + str(test_list2))

# Similar index elements frequency
# using list comprehension + enumerate()
res = len([key for key, val in enumerate(zip(test_list1, test_list2)) if val[0] == val[1]])

# printing result
print ("Number of elements having similar index : " + str(res))

Output :

The original list 1 is : [1, 3, 5, 6, 8]
The original list 2 is : [4, 3, 6, 6, 10]
Number of elements having similar index : 2