...and then you'd have to `eval` that long string to get an array which would be even slower, not to say completely unsafe 😉

If your calculation takes 2 hours, then I'd say replacing `for` loops with manually typed array accesses is not the best place to optimize. Most likely something else takes long to finish.

Have you tried [profiling your code](https://docs.python.org/3/library/profile.html)?