René's URL Explorer Experiment

Title: bpo-15873: Implement [date][time].fromisoformat by pganssle · Pull Request #4699 · python/cpython · GitHub

Open Graph Title: bpo-15873: Implement [date][time].fromisoformat by pganssle · Pull Request #4699 · python/cpython

X Title: bpo-15873: Implement [date][time].fromisoformat by pganssle · Pull Request #4699 · python/cpython

Description: Per discussion on the python-dev mailing list, this is a C implementation of fromisoformat as alternate constructors for datetime, date and time, resolving this issue. If it is deemed desirable, it can be extended later to cover all ISO-8601 datetime strings, but I believe the consensus so far is to have a minimum implementation that only covers the outputs of datetime.isoformat(). One thing I'd like to call attention to is that my profiling seems to indicate that in the common case (i.e. not calling this from a subclass), using the C API directly is much faster than going through PyObject_CallFunction. Here is a profiling script: from datetime import datetime from datetime import timezone, timedelta from timeit import default_timer as timer N = 100000 tzi = timezone(timedelta(hours=4)) tzi = None comps = (2014, 3, 25, 4, 17, 30, 204300, tzi) dt = datetime(*comps) s = timer() for i in range(N): dt_c = datetime(2014, 3, 25, 4, 17, 30, 241300, tzinfo=tzi) e = timer() tt = 1000000000 * (e - s) / N dtstr = dt.isoformat() s = timer() for i in range(N): dt_fi = datetime.fromisoformat(dtstr) e = timer() tt2 = 1000000000 * (e - s) / N print('datetime constructor: {:0.1f}ns'.format(tt)) print('fromisoformat: {:0.1f}ns'.format(tt2)) Result on my laptop: (tzi is None): datetime constructor: 2294.1ns fromisoformat: 944.5ns (tzi = timezone(timedelta(hours=4))) datetime constructor: 2229.1ns fromisoformat: 1400.5ns If there's no particularly pressing reason why all the other alternate constructors universally go through the main constructor call, I could write a small function or macro that would take the fast path if available and use it for all the alternate constructors. CC @abalkin @mariocj89 https://bugs.python.org/issue15873

Open Graph Description: Per discussion on the python-dev mailing list, this is a C implementation of fromisoformat as alternate constructors for datetime, date and time, resolving this issue. If it is deemed desirable, it...

X Description: Per discussion on the python-dev mailing list, this is a C implementation of fromisoformat as alternate constructors for datetime, date and time, resolving this issue. If it is deemed desirable, it...

Opengraph URL: https://github.com/python/cpython/pull/4699

X: @github

direct link

Domain: github.com

Links:

Viewport: width=device-width