first and last methods used excluded items-CodePudding

i used last() to get last item of queryset after exclude some items as below:

holidays = HolidayModel.objects.all().values_list('date', flat=True)
result = BorseExchangeLog.objects.exclude(
hint_time__date__in=holidays
)
# output 1
print(list(result.valuse_list('hint_time__date',flat=True).distinct('hint_time__date')))
#output2
print(result.last().hint_time.date())

but in output2 print item that not exists in output1

i test some other codes as below:

print(list(logs.values_list('hint_time__date',flat=True).distinct('hint_time__date')))
print(list(logs.values_list('hint_time__date', flat=True).distinct('hint_time__date'))[-1])
print(logs.order_by('hint_time__date').last().hint_time.date())


[..., datetime.date(2020, 10, 21), datetime.date(2020, 10, 26)]
2020-10-26
2020-10-25

my holiday model:

class HolidayModel(models.Model):
    creator = models.ForeignKey('accounts.Account', on_delete=models.PROTECT, verbose_name=_('Creator'))
    reason = models.CharField(default='', max_length=200, verbose_name=_('Reason'))
    date = models.DateField(default=timezone.now, verbose_name=_('Date'))

and other model is :

class BorseExchangeLog(models.Model):
    create_time = models.DateTimeField(default=timezone.now)
    hint_time = models.DateTimeField(default=timezone.now)

i test that by first() and problem was there too

what is problem? my code is wrong or bug from django orm?

using django2.2 and postgresql

CodePudding user response：

Your datetimes are timezone aware but the date() method on datetime objects does not take the timezone into account, __date will take the timezone into account provided your DB supports it. Use the django.utils.timezone.localdate function to get a date taking into account the timezone

from django.utils.timezone import localdate
print(localdate(result.last().hint_time))