Not only is the latter easier to read, it's hundreds of times faster than the for loop (and provides opportunities for hidden vectorization and parallelization). However, the Numpy abstraction stops ...

A Python library for numpy arrays that persist on disk in a format that is simple, self-documented and tool-independent, and maximizes universal readability.

Python is convenient and flexible, yet notably slower than other languages for raw computational speed. The Python ecosystem has compensated with tools that make crunching numbers at scale in Python ...