Show the : character in the timezone offset using datetime.strftime
datetime, python, timezone, timezone-offset
Solution
Datetime is implemented in C. There you find that the function for `tp_str`, which is used by Pythons `str` by default, just calls `isoformat()`.
Further the `datetime.strftime` method calls the libc `strftime` function, which gives the timezone difference without a seperator, whereas `datetime.isoformat` calls a method, which is implemented for Python directly, where a separator can be passed, which is the colon in this case.
Problem
What is the format string to give to `strftime` which would give the same output as I see for `isoformat(' ')`? ``` >>> from datetime import datetime >>> import pytz >>> dt = datetime.now(tz=pytz.UTC).replace(microsecond=0) >>> print dt 2014-05-29 13:11:00+00:00 >>> dt.isoformat(' ') '2014-05-29 13:11:00+00:00' >>> dt.strftime('%Y-%m-%d %H:%M:%S%z') '2014-05-29 13:11:00+0000' ``` Where does the `__str__` behaviour of datetime get that extra colon in the offset from? I looked in the formatting options and could only find %z and %Z for +HHMM or name respectively. I looked at the implementation of `datetime.__str__` but got no hints, it just says `pass` (?!). I think it eventually delegates to `isoformat(' ')` but I don't understand how/where that is implemented.