Convert string datetime with 9 digits in last to ISO format datetime object in python

Question

I have string datetime (eg: "2022-11-11T06:19:32.776289776Z"). I want to convert the same in ISO format.

I tried below

>>> datetime.datetime.fromisoformat("2022-11-11T06:19:32.776289776Z")

But it is throwing error.

ValueError: Invalid isoformat string: '2022-11-11T06:19:32.776289776Z

It is working if I give only 6 digits in the last without Z.

Below example is working for me, however not working for the strings with 9 digits and z in the end:

>>> datetime.datetime.fromisoformat("2022-11-11T06:19:32.776289")

datetime.datetime(2022, 11, 11, 6, 19, 32, 776289)

Answer 1

If Python 3.11 is available

If you can upgrade to Python 3.11, then fromisoformat can handle this:

# Python 3.11 and above only
dt = datetime.datetime.fromisoformat("2022-11-11T06:19:32.776289776Z")
print(dt)

giving

2022-11-11 06:19:32.776289+00:00

Earlier versions of Python

If you're restricted to earlier versions of Python, then as @SalmanA said in the comments, you can get to a valid timestamp by (1) trimming the microseconds down to 6 digits, using re.sub, and (2) replacing Z with +00:00 (str.replace will do that).

This assumes the timestamp is otherwise validly formatted (e.g. no letter Z anywhere else in the string).

For example:

import datetime
import re

def clean_str(ts):
    return re.sub("(\d{6})(\d+)", r"\1", ts).replace("Z", "+00:00")

tests = ["2022-11-11T06:19:32.776289776Z",
         "2022-11-11T06:19:32.776289Z",
         "2022-11-11T06:19:32.7762897+03:00",
         "2022-11-11T06:19:32.776Z"]

for i, ts in enumerate(tests, 1):
    clean = clean_str(ts)
    dt = datetime.datetime.fromisoformat(clean)
    print(f"({i}): {ts} -> {clean} -> {dt}")

giving:

(1): 2022-11-11T06:19:32.776289776Z -> 2022-11-11T06:19:32.776289+00:00 -> 2022-11-11 06:19:32.776289+00:00
(2): 2022-11-11T06:19:32.776289Z -> 2022-11-11T06:19:32.776289+00:00 -> 2022-11-11 06:19:32.776289+00:00
(3): 2022-11-11T06:19:32.7762897+03:00 -> 2022-11-11T06:19:32.776289+03:00 -> 2022-11-11 06:19:32.776289+03:00
(4): 2022-11-11T06:19:32.776Z -> 2022-11-11T06:19:32.776+00:00 -> 2022-11-11 06:19:32.776000+00:00

Note that as (1) and (3) show, the microseconds are truncated, not rounded, i.e. 32.776289776 goes to 32.776289 not 32.776290. (And the same goes for the native Python 3.11 solution.) If you wanted true rounding then you would need to parse the string further.