Closest Pair to Kth index element in Tuple using Python

When working with tuples, you may need to find the tuple from a list that has the closest value to a reference tuple at a specific index position. Python's enumerate() method combined with abs() function provides an efficient solution.

Problem Statement

Given a list of tuples and a reference tuple, find which tuple in the list has the value closest to the reference tuple's Kth index element ?

Example

tuple_list = [(5, 6), (66, 76), (21, 35), (90, 8), (9, 0)]

print("The list is:")
print(tuple_list)

reference_tuple = (17, 23)
print("The reference tuple is:")
print(reference_tuple)

K = 2
print("The value of K has been initialized to:")
print(K)

min_diff, result_index = float('inf'), None
for idx, val in enumerate(tuple_list):
    diff = abs(reference_tuple[K - 1] - val[K - 1])
    if diff < min_diff:
        min_diff, result_index = diff, idx

print("The tuple nearest to Kth index element is:")
print(tuple_list[result_index])

The list is:
[(5, 6), (66, 76), (21, 35), (90, 8), (9, 0)]
The reference tuple is:
(17, 23)
The value of K has been initialized to:
2
The tuple nearest to Kth index element is:
(21, 35)

How It Works

The algorithm compares the Kth index element (index K-1) of the reference tuple with the same index element in each tuple from the list:

• Reference tuple at index 1: reference_tuple[1] = 23

• Compare with each tuple's second element: 6, 76, 35, 8, 0

• Calculate absolute differences: |23-6|=17, |23-76|=53, |23-35|=12, |23-8|=15, |23-0|=23

• Minimum difference is 12, so (21, 35) is the closest tuple

Alternative Implementation

Here's a more concise version using the min() function ?

tuple_list = [(5, 6), (66, 76), (21, 35), (90, 8), (9, 0)]
reference_tuple = (17, 23)
K = 2

closest_tuple = min(tuple_list, key=lambda x: abs(reference_tuple[K-1] - x[K-1]))
print("The tuple nearest to Kth index element is:")
print(closest_tuple)

The tuple nearest to Kth index element is:
(21, 35)

Conclusion

Use enumerate() with abs() to find the closest tuple by tracking minimum differences. The min() function with a lambda key provides a more concise alternative for the same result.