New submission from leewz:

Current: If I want to create a datetime object with a particular timezone 
offset, I have to do this:
    
    import datetime
    mytime = datetime.datetime(2015, 10, 16, 9, 13, 0, 
tzinfo=datetime.timezone(datetime.timedelta(hours=-7)))

Or with imports:

    from datetime import datetime, timezone, timedelta
    mytime = datetime(2015, 10, 16, 9, 13, 0, 
tzinfo=timezone(timedelta(hours=-7)))

That's two extra imports and two extra objects created.


Requested way:
    mytime = datetime(2015, 10, 16, 9, 13, 0, tzinfo=-7)
    # mytime.tzinfo == -7

Or if someone doesn't like the `tzinfo` keyword:
    mytime = datetime(2015, 10, 16, 9, 13, 0, tzhours=-7)
    # mytime.tzinfo == timezone(timedelta(-7))


For timezones, hours are the normal unit of time. At least, I think about time 
zones in hours, and I don't know who would think about them in minutes. There 
are half-hour offsets, so floats make sense to have.

Imagine you have about a year of experience dabbling in Python, and you're 
trying to do a relatively simple task, like reading PDT times and converting 
them to local time. You would go to the datetime docs, see that you need to 
pass in a tzinfo object. You look that up, and run into this:
"""tzinfo is an abstract base class, meaning that this class should not be 
instantiated directly. You need to derive a concrete subclass, and (at least) 
supply implementations of the standard tzinfo methods needed by the datetime 
methods you use."""

Well, great. If you want to convert times, you'll have to subclass an abstract 
base class, and implement five methods. You'd probably have to read the whole 
docs for this class, too. (The docs for tzinfo take nine Page Downs for me to 
scroll past.)

If you're not frightened off by the first two sentences, you'll see that 
there's the concrete subclass `datetime.timezone`. We're two levels down, now. 
Going there, you'll see that you need to pass in a timedelta object. Three 
levels. You need to learn about three classes just to specify an hour offset.

Timezones are something that many non-programmers understand, and the rules are 
pretty simple (barring DST, but the library doesn't really deal with it 
anyway). Ideally, it should be simple to do simple things.


PS: There seems to be unnecessary inconsistency with `.astimezone`, 
`fromtimestamp`, and `now` taking a `tz` kwarg rather than a `tzinfo` kwarg.

----------
assignee: docs@python
components: Documentation, Library (Lib)
messages: 253111
nosy: docs@python, leewz
priority: normal
severity: normal
status: open
title: Have `datetime` understand integer arguments for timezones
type: enhancement
versions: Python 3.5, Python 3.6

_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue25428>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

Reply via email to