Convert an RFC 3339 nano time to Python datetime

Question

Is there an easy way to convert an RFC 3339 nano time into a regular Python timestamp?

For example, time = '2022-07-14T12:01:25.225089838+08:00', I found a way using datetime

from datetime import datetime

time = '2022-07-14T12:01:25.225089+08:00'
date = datetime.fromisoformat(time)  # good

time = '2022-07-14T12:01:25.225089838+08:00'
date = datetime.fromisoformat(time)  # error

It works with string like '2022-07-14T12:01:25.225089+08:00', but it doesn't work with the time above.

Possible duplicate https://stackoverflow.com/questions/10611328/parsing-datetime-strings-containing-nanoseconds — Kota Mori, Jul 14 '22 at 06:26
ISO 8601 doesn't do nanoseconds, and neither does the Python datetime class. You can use string slicing to remove those three characters. — Tim Roberts, Jul 14 '22 at 06:26

Ice · Answer 1 · 2022-07-20T06:05:52.933

There are a few ways to do it. Depends on what is the input format and how you define an easy way. There are actually many post asking similar issues you have. I'll post a few at the end for your reference if you are interested and please check next time before posting.

The main issue of datetime object is that it only holds 6 digit after second. You will need a different data structure to save it if you want to preserve all of the digits.

If you are ok with cutting off at 6 digit, FObersteiner's answer is perfect. Another methodology is vanilla datetime string parsing

from datetime import datetime
date = '2022-07-14T12:01:25.225089838+08:00'.removesuffix('+08:00')
x = datetime.strptime( date[:-3], '%Y-%m-%dT%H:%M:%S.%f')

If you would like to preserve all the digits. You may want to create your own class extending from the datetime class or create some function for it.

A little heads-up: `removesuffix()` is Python 3.9+ – oelna Nov 17 '22 at 13:41 — oelna, Nov 17 '22 at 13:41

FObersteiner · Answer 2 · 2022-07-14T06:49:02.920

from datetime.fromisoformat docs:

Caution: This does not support parsing arbitrary ISO 8601 strings - it is only intended as the inverse operation of datetime.isoformat(). A more full-featured ISO 8601 parser, dateutil.parser.isoparse is available in the third-party package dateutil.

dateutil's isoparse will do the job:

from dateutil.parser import isoparse

time = '2022-07-14T12:01:25.225089838+08:00'
date = isoparse(time) 

print(date)
# 2022-07-14 12:01:25.225089+08:00

print(repr(date))
# datetime.datetime(2022, 7, 14, 12, 1, 25, 225089, tzinfo=tzoffset(None, 28800))

Note: it doesn't round to microseconds, it just slices off the last 3 decimal places. So basically, if you're dealing with a standardized format like RFC 3339, you can do the slicing yourself like

from datetime import datetime

time = '2022-07-14T12:01:25.225089838+08:00'
date = datetime.fromisoformat(time[:-9] + time[-6:])

print(date)
# 2022-07-14 12:01:25.225089+08:00

Convert an RFC 3339 nano time to Python datetime

2 Answers2