Convert date to datetime in Python

You can use datetime.combine(date, time); for the time, you create a datetime.time object initialized to midnight.

from datetime import date
from datetime import datetime

dt = datetime.combine(date.today(), datetime.min.time())

There are several ways, although I do believe the one you mention (and dislike) is the most readable one.

>>> t=datetime.date.today()
>>> datetime.datetime.fromordinal(t.toordinal())
datetime.datetime(2009, 12, 20, 0, 0)
>>> datetime.datetime(t.year, t.month, t.day)
datetime.datetime(2009, 12, 20, 0, 0)
>>> datetime.datetime(*t.timetuple()[:-4])
datetime.datetime(2009, 12, 20, 0, 0)

and so forth -- but basically they all hinge on appropriately extracting info from the date object and ploughing it back into the suitable ctor or classfunction for datetime.

You can use the date.timetuple() method and unpack operator *.

args = d.timetuple()[:6]
datetime.datetime(*args)

you can also use

date = datetime.utcnow().date()
dt = datetime.fromisoformat(date.isoformat())

print(dt)

datetime.datetime(2021, 11, 15, 0, 0)

Do I really have to manually call datetime(d.year, d.month, d.day)

No, you'd rather like to call

date_to_datetime(dt)

which you can implement once in some utils/time.py in your project:

from typing import Optional
from datetime import date, datetime

def date_to_datetime(
    dt: date,
    hour: Optional[int] = 0,
    minute: Optional[int] = 0, 
    second: Optional[int] = 0) -> datetime:

    return datetime(dt.year, dt.month, dt.day, hour, minute, second)

To make dt timezone aware datetime (with Django timezone util):

from django.utils import timezone


timezone.now().replace(*(*dt.timetuple()[:6], 0))

You can use this class:

import time 

import datetime

class TimingClass():

    def __init__(self):

        self.YEAR        = datetime.date.today().year
        self.MONTH       = datetime.date.today().month
        self.DATE        = datetime.date.today().day
        self.HOUR        = datetime.datetime.now().hour
        self.MINUTE      = datetime.datetime.now().minute
        self.SECONDS     = datetime.datetime.now().second
        
        self.TODAY       = datetime.date.today()
        self.YESTERDAY   = datetime.datetime.strftime( (self.TODAY - datetime.timedelta(days = 1)) , '%Y-%m-%d')
        self.TOMORROW   = datetime.datetime.strftime( (self.TODAY + datetime.timedelta(days = 1)) , '%Y-%m-%d')
        
        self.TODAY_datetime = datetime.datetime.combine(datetime.date.today(), datetime.datetime.min.time())

If you need something quick, datetime_object.date() gives you a date of a datetime object.