unable to substract two timefeild in django

Question

Hi Team i have models as below. And i am trying to substract out time and in time .

class Attendance(models.Model):
   employee = models.ForeignKey(Employee, on_delete=models.CASCADE,
                                default=1, related_name='Attendance')
    attendance_date = models.DateField(null=True)
    in_time = models.TimeField(null=True)
    out_time = models.TimeField(null=True, blank=True)
    totaltime = models.TimeField(null=True, blank=True)

    def __str__(self):
        return str(self.employee) + '-' + str(self.attendance_date)

    @property
    def totaltime(self):
        FMT = '%H:%M:%S'
        currentDate = date.today().strftime('%Y-%m-%d')
        sub = datetime.strptime('out_time', FMT) -
            datetime.strptime('in_time', FMT)
        return sub

Still getting and error: ValueError: time data 'out_time' does not match format '%H:%M:%S'

Please advise what should i do ,I am expecting how i will substract two timefeild

Myth · Answer 1 · 2023-01-05T11:11:25.190

0

@property
def totaltime(self):
    total_time = datetime.timedelta(hours=self.out_time.hour, minutes=self.out_time.minute,
                                    seconds=self.out_time.second) - datetime.timedelta(hours=self.in_time.hour,
                                                                                      minutes=self.in_time.minute,
                                                                                      seconds=self.in_time.second)
    return total_time

edited Jan 05 '23 at 11:11

answered Jan 05 '23 at 11:01

Myth

338
7

Again error comes : TypeError: strptime() argument 1 must be str, not datetime.time – Anuradha Rajput Jan 05 '23 at 11:05
i did this in_time = datetime.strptime(str(self.in_time), FMT) out_time = datetime.strptime(str(self.out_time), FMT) still error comes : alueError: time data 'None' does not match format '%H:%M:%S' – Anuradha Rajput Jan 05 '23 at 11:08
can you try now, I edited my answer. Your in_time and out_time was already TimeField – Myth Jan 05 '23 at 11:13
i tried but Exception Value: type object 'datetime.datetime' has no attribute 'timedelta' /. – Anuradha Rajput Jan 05 '23 at 11:23
unable to sort the issue – Anuradha Rajput Jan 05 '23 at 11:38

Niko · Answer 2 · 2023-01-06T09:29:10.780

So, first, you are using total_time as a @property, so you can just drop the field. Second, you need to use timedelta to calculate the difference between times, which is where another problem arises, because it seems only to operate with datetime objects, so you must work around that:

models.py:

from datetime import datetime, date, timedelta

class Attendance(models.Model):
    employee = models.ForeignKey(Employee, on_delete=models.CASCADE,
                                default=1, related_name='Attendance')
    attendance_date = models.DateField(null=True)
    in_time = models.TimeField(null=True)
    out_time = models.TimeField(null=True, blank=True)

    def __str__(self):
        return str(self.employee) + '-' + str(self.attendance_date)

    @property
    def total_time(self):
        total = ( datetime.combine(date.today(), self.out_time) - 
                  timedelta(
                        hours=self.in_time.hour, 
                        minutes=self.in_time.minute, 
                        seconds=self.in_time.second
                    ) 
                )
        return total.time()

tests.py

class AttendanceTestCase(TestCase):
    def setUp(self):
        self.target_hour = 1
        self.target_minutes = 42
        self.target_seconds = 36

        now = datetime.now()
        in_time = time(now.hour, now.minute, now.second)
        dt = (datetime.combine(date.today(), in_time) + 
                timedelta(
                    hours=self.target_hour, 
                    minutes=self.target_minutes, 
                    seconds=self.target_seconds
                )
            )
        out_time = dt.time()
        
        self.employee = Employee.objects.create(
            username='employee',
            password='super_secret',
            email='employee@example.com'
        )

        self.attendance = Attendance.objects.create(
            employee=self.employee,
            attendance_date=date.today(),
            in_time=in_time,
            out_time=out_time
        )
        
    def test_attendance_total_time(self):
        total_time = self.attendance.total_time
        self.assertEqual(total_time.hour, self.target_hour)
        self.assertEqual(total_time.minute, self.target_minutes)
        self.assertEqual(total_time.second, self.target_seconds)
        print(total_time)

hi sir thanks for the ans it do not given any error but still it is returning none to me — Anuradha Rajput, Jan 06 '23 at 05:44

unable to substract two timefeild in django

2 Answers2