Benchmark Key Value Swapping of a Dictionary in Python

Today, I was writing a python script and needed to swap the keys and values in a dictionary. While doing it, I wanted to see how long it takes to perform such a swap operation on small dictionaries.

To determine which solution is the fastest on CPU, we can use the timeit module in Python to benchmark each solution.

The methods I will be testing is that

1. A similar way to list comprehension
2. using zip()
3. Iterating the dictionary keys with for loop

Here’s an example benchmark:

import timeit

existing_dict = {"a": 1, "b": 2, "c": 3}

def solution1():
    return {v: k for k, v in existing_dict.items()}

def solution2():
    return dict(zip(existing_dict.values(), existing_dict.keys()))

def solution3():
    swapped_dict = {}
    for k, v in existing_dict.items():
        swapped_dict[v] = k
    return swapped_dict

print("Solution 1:", timeit.timeit(solution1, number=100000))
print("Solution 2:", timeit.timeit(solution2, number=100000))
print("Solution 3:", timeit.timeit(solution3, number=100000))

This code benchmarks each solution by running it 100,000 times and measuring the time it takes to complete.

Results

On my machine, the results are:

Solution 1: 0.245 seconds
Solution 2: 0.342 seconds
Solution 3: 0.445 seconds

Don’t forget that these results may vary depending on the size of the input dictionary and the specific hardware and software configuration of your machine.