The main difference is the strings are stored in a single contiguous arena buffer (with some minor caveats if you mutate the array in-place). With object string

The main difference is the strings are stored in a single contiguous arena buffer (with some minor caveats if you mutate the array in-place). With object strings each string has its own heap allocation. More details in NEP 55: https://numpy.org/neps/nep-0055-string_dtype.html https://numpy.org/neps/nep-0055-string_dtype.html This post is based on the content of a 25 minute talk and it’s hard to explain everything fully…