George Sakkis <george.sak...@gmail.com> added the comment: > In that case, I think it best to leave nsmallest/nlargest as-is. By > appending ties to the result, it becomes harder to implement policy > decisions on what to do with those ties (perhaps listing them separately > or splitting their prizes n-ways).
I wouldn't worry about the further post-processing too much; it's optional and up to the client to implement if necessary (in my current use case it's not). Regardless, that's orthogonal to having a general, reliable and efficient function in the standard library that reduces an initial sequence of thousands/millions down to a dozen or two, preserving the ties. > A preferred approach is to use > existing tools such as: last=result[1]; [last]*s.count(last). > Alternatively, result=sorted(s) works well with bisect to find the cut > points. Also, my instincts say that it is weird ask for n-items and get > a result with potentially more than n. That's a documentation issue, it would be explicitly addressed in the description of `ties`. I'm not proposing to change the current default behavior; the whole change would be fully backwards compatible. > Looking at the source code for nsmallest/nlargest, I think this > build-out would complicate the code quite a bit, so the use cases would > need to be more compelling. The way the nsmallest/nlargest work is that > they maintain an n-length buffer and loop over the entire input while > remembering only the best-n-so-far. That approach doesn't easily extend > to tracking best-n-so-far-and-all-ties. I haven't thought about the implementation yet but before I do, would a patch help reopen this ticket ? If so, I'm willing to take a stab at it. ---------- status: closed -> open _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue5669> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
