How to parse str(my_datetime) using strptime?
datetime, python, strptime, timezone
Solution
Note that `str(d)` is documented as being equivalent to `d.isoformat(' ')`. This starts with `%Y-%m-%d %H:%M:%S` (`2017-01-01 00:00:00`), but then:
- Either has nothing or `.%f`, depending whether the microseconds part is nonzero.
- Either has nothing or an offset like `+HH:MM`, depending whether the instance is timezone-aware.
`datetime.strptime` doesn't have support for optional parts, therefore there isn't a single `format` parameter that can match all of the possible outputs.
In Python 3.7+, you can use `datetime.fromisoformat` to parse `datetime.isoformat` output. Contributed by Paul Ganssle in issue15873.
Problem
This is the default string representation of a datetime: ``` >>> from datetime import datetime, timezone >>> dt = datetime(2017, 1, 1, tzinfo=timezone.utc) >>> print(dt) 2017-01-01 00:00:00+00:00 ``` What is the correct format string to parse that with `datetime.strptime`? That is, what format goes in place of the "???" to consistently have the following invariant: ``` >>> dt == datetime.strptime(str(dt), "???") True ```