On Tue, Sep 22, 2015 at 10:43 AM, Guido van Rossum <gu...@python.org> wrote:
> Based on the UTC/local diagram from the "Mind the Gap" section, am I >> correct in thinking that the modified invariant that also covers times >> in a gap is: >> >> dt == >> datetime.fromtimestamp(dt.astimezone(utc).astimezone(dt.tzinfo).timestamp()) >> >> That is, for local times that exist, the invariant "dt == >> dt.astimezone(utc).astimezone(dt.tzinfo)" holds, but for times that >> don't exist, "dt.astimezone(utc).astimezone(dt.tzinfo)" will normalise >> them to be a time that actually exists in the original time zone, and >> that normalisation also effectively happens when calling >> "dt.timestamp()". >> > > That can't be right -- There is no way any fromtimestamp() call can return > a time in the gap. > I don't think Nick said that. > I think about the only useful invariant here is > > dt.timestamp() == dt.astimezone(utc).timestamp() == dt.astimezone(<any > other tz>).timestamp() > Yes, this is just another way to say that .astimezone() conversions are now "lossless."
_______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
