Performance deep dive

In this article, we'll examine the performance difference between approaches for rotational cipher in Python.

The [approaches page][approaches] lists four approaches to this exercise:

1. Using recursion
2. Using str.translate
3. Using ascii values
4. Using the alphabet

Benchmarks

To benchmark the approaches, we wrote a small benchmark application using the timeit library. These tests were run in Windows 11, using Python 3.11.1. Your system results may vary.

rotate ascii long : 0.000189200000022538
rotate alphabet long : 0.0002604000037536025
rotate translate long : 1.3999990187585354e-05
rotate recursion long : 0.001309900006162934

rotate ascii short : 4.999994416721165e-06
rotate alphabet short : 3.6999990697950125e-06
rotate translate short : 1.0200004908256233e-05
rotate recursion short : 5.4000120144337416e-06

Conclusion

For a long string as input, the str.translate approach is the fastest, followed by ascii, alphabet, and finally recursion. For a short string as input, is the alphabet approach the fastest, followed by ascii, recursion and finally str.translate.

This means that if you know the input is a short string, the fastest approach is to use the alphabet, and forgo the overhead of making and saving a translation dictionary. On the other hand, if the input is a long string, the overhead of making a dictionary is amortized over the length of the text to be translated, and the fastest approach becomes str.translate.