Opened 13 years ago
Closed 13 years ago
#16906 closed Cleanup/optimization (fixed)
Avoid strftime when isoformat can do the job
Reported by: | Aymeric Augustin | Owned by: | nobody |
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Component: | Core (Other) | Version: | 1.3 |
Severity: | Normal | Keywords: | |
Cc: | Triage Stage: | Ready for checkin | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
While working on timezone support in Django, the inconsistency in these three functions surprised me: https://code.djangoproject.com/browser/django/trunk/django/db/backends/__init__.py#L714
In fact, r7946 introduced a datetime_safe
module that provides a Python implementation of datetime.[date|datetime].strftime
for dates before 1900.
However, this is overkill for the purpose of just showing a date
or datetime
in ISO format (%Y-%m-%d
and %Y-%m-%d %H:%M:%S
). It makes the code needlessly complicated, sometimes inconistent, and inefficient. The isoformat
method achieves the same result, works for any date, and is implemented in C.
Also, some code still uses the strftime
function from the standard library. Using isoformat
is better because it isn't subject to the 1900 limit.
See attached patch.
For more background, see isoformat_date
in http://svn.python.org/view/python/tags/r271/Modules/datetimemodule.c?view=markup. Note that date
objects have no __unicode__
and their __str__
just call isoformat
, so str(date)
or unicode(date)
is the same as datetime_safe.date(date.year, date.month, date.day).strftime('%Y-%m-%d')
. It's pretty much the same for datetime
objects, except that isoformat
uses T
as a separator, while str
and unicode
use a space.
Changing date.format('%Y-%m-%d')
to date.isoformat()
is safe. Changing datetime.format('%Y-%m-%d %H:%M:%S')
to datetime.isoformat()
requires removing the microseconds and the timezone first, if there is one, so the correct pattern is datetime.replace(microsecond=0, tzinfo=None)
. This also applies for time objects.
Attachments (1)
Change History (4)
by , 13 years ago
Attachment: | 16906.patch added |
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comment:1 by , 13 years ago
Description: | modified (diff) |
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comment:2 by , 13 years ago
Triage Stage: | Unreviewed → Ready for checkin |
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comment:3 by , 13 years ago
Resolution: | → fixed |
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Status: | new → closed |
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