[Python-Dev] iso8601 parsing (original) (raw)

Skip Montanaro skip.montanaro at gmail.com
Tue Nov 28 16:09:14 EST 2017

It's got its own little parsing language, different than the usual strftime/strptime format scheme, more like what you might see in Excel. I never worried too much about the speed of dateutil.parser.parse() unless I was calling it in an inner loop, but arrow.get() seems to be a fair bit faster than dateutil.parser.parse. This makes sense, as the latter tries to figure out what you've given it (you never give it a format string), while in the absence of a format string, arrow.get assumes you have an ISO-8601 date/time, with only a few small variations allowed.

Skip

On Tue, Nov 28, 2017 at 2:52 PM, Paul G <paul at ganssle.io> wrote:

IIRC, arrow usually calls dateutil to parse dates anyway, and there are many other, lighter dependencies that will parse an ISO 8601 date quickly into a datetime.datetime object.

I still think it's reasonable for the .isoformat() operation to have an inverse operation in the standard library. On November 28, 2017 3:45:41 PM EST, Skip Montanaro <_ _skip.montanaro at gmail.com> wrote:

I think the latest version can now strptime offsets of the form ±HH:MM with %z, so there's no longer anything blocking you from parsing from all isoformat() outputs with strptime, provided you know which one you need.

Or just punt and install arrow: import arrow arrow.get('2017-10-20T08:20:08.986166+00:00')

<Arrow [2017-10-20T08:20:08.986166+00:00]> arrow.get('2017-10-20T08:20:08.986166+00:00').datetime datetime.datetime(2017, 10, 20, 8, 20, 8, 986166, tzinfo=tzoffset(None, 0)) Skip -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20171128/8d756c52/attachment-0001.html>

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