Bug report
Bug description:
I know that there were discussions about rewriting CSV Sniffer, and they seem to be on hold, to avoid breaking any code relying on its behavior.
I believe it's possible, though, to still make it significantly faster.
The current code iterates over 127 ASCII characters and counts their occurences on each line, even if they're not present:
| for char in ascii: |
It's highly inefficient. We can count only present characters, and backfill zeros.
CPython versions tested on:
3.15
Operating systems tested on:
macOS