[fnl]

Thank you for the very nice, educative article, Bruno!

If performance comparison of counting character pairs really were the issue here, in addition to the already suggested numpy approach, an implementation I'd dare wager to be as competitive is re2, e.g. [1], a drop-in replacement for the standard re package.

But I want to point out that I think all this performance comparison of this trivial character counting distracts from the core idea here: You'd use a low-level implementation in Rust (or C/C++/Cython, for that matter) when such "nifty tricks" are not available, after all. So again thanks for the article, and do think if you really want this performance issues to degrade the article to a only marginally relevant performance "showdown".

https://pypi.python.org/pypi/re2/