What's the most elegant way to get the end of the day (datetime)?

Question

I'm currently writing some reporting code that allows users to optionally specify a date range. The way it works (simplified), is:

• A user (optionally) specifies a year.
• A user (optionally) specifies a month.
• A user (optionally) specifies a day.

Here's a code snippet, along with comments describing what I'd like to do:

from datetime import datetime, timedelta

# ...

now = datetime.now()
start_time = now.replace(hour=0, minute=0, second=0, microsecond=0)
stop_time = now
# If the user enters no year, month, or day--then we'll simply run a
# report that only spans the current day (from the start of today to now).

if options['year']:
    start_time = start_time.replace(year=options['year'], month=0, day=0)
    stop_time = stop_time.replace(year=options['year'])
    # If the user specifies a year value, we should set stop_time to the last
    # day / minute / hour / second / microsecond of the year, that way we'll
    # only generate reports from the start of the specified year, to the end
    # of the specified year.

if options['month']:
    start_time = start_time.replace(month=options['month'], day=0)
    stop_time = stop_time.replace(month=options['month'])
    # If the user specifies a month value, then set stop_time to the last
    # day / minute / hour / second / microsecond of the specified month, that
    # way we'll only generate reports for the specified month.

if options['day']:
    start_time = start_time.replace(day=options['day'])
    stop_time = stop_time.replace(day=options['day'])
    # If the user specifies a day value, then set stop_time to the last moment of
    # the current day, so that reports ONLY run on the current day.

I'm trying to find the most elegant way to write the code above--I've been trying to find a way to do it with timedelta, but can't seem to figure it out. Any advice would be appreciated.

Answer 1

After looking at some of the answers here, and not really finding anything extremely elegant, I did some poking around the standard library and found my current solution (which I like quite well): dateutil.

Here's how I implemented it:

from datetime import date
from dateutil.relativedelta import relativedelta

now = date.today()
stop_time = now + relativedelta(days=1)
start_time = date(
    # NOTE: I'm not doing dict.get() since in my implementation, these dict
    # keys are guaranteed to exist.
    year = options['year'] or now.year,
    month = options['month'] or now.month,
    day = options['day'] or now.day
)

if options['year']:
    start_time = date(year=options['year'] or now.year, month=1, day=1)
    stop_time = start_time + relativedelta(years=1)

if options['month']:
    start_time = date(
        year = options['year'] or now.year,
        month = options['month'] or now.month,
        day = 1
    )
    stop_time = start_time + relativedelta(months=1)

if options['day']:
    start_time = date(
        year = options['year'] or now.year,
        month = options['month'] or now.month,
        day = options['day'] or now.day,
    )
    stop_time = start_time + relativedelta(days=1)

# ... do stuff with start_time and stop_time here ...

What I like about this implementation, is that python's dateutil.relativedata.relativedata works really well on edge cases. It gets the days/months/years correct. If I have month=12, and do relativedata(months=1), it'll increment the year and set the month to 1 (works nicely).

Also: in the above implementation, if the user specifies none of the optional dates (year, month, or day)--we'll fallback to a nice default (start_time = this morning, stop_time = tonight), that way we'll default to doing stuff for the current day only.

Thanks to everyone for their answers--they were helpful in my research.

Answer 2

date = datetime.strftime('<input date str>')

date.replace(hour=0, minute=0, second=0, microsecond=0)  # now we get begin of the day
date += timedelta(days=1, microseconds=-1)  # now end of the day

Answer 3

from datetime import datetime, date, timedelta

def get_current_timestamp():
    return int(datetime.now().timestamp())

def get_end_today_timestamp():
    # get 23:59:59
    result = datetime.combine(date.today() + timedelta(days=1), datetime.min.time())
    return int(result.timestamp()) - 1

def get_datetime_from_timestamp(timestamp):
    return datetime.fromtimestamp(timestamp)

end_today = get_datetime_from_timestamp(get_end_today_timestamp())

Answer 4

    today = datetime.date.today()
    begintime = today.strftime("%Y-%m-%d 00:00:00")
    endtime = today.strftime("%Y-%m-%d 23:59:59")

Answer 5

Using dict.get can simplify your code. It is a bit cleaner than using datetime.replace and timedelta objects.

Here's something to get you started:

from datetime import datetime

options = dict(month=5, day=20)
now = datetime.now()
start_time = datetime(year=options.get('year', now.year), 
                      month=options.get('month', 1),
                      day=options.get('day', 1)
                      hour=0,
                      minute=0,
                      second=0)
stop_time =  datetime(year=options.get('year', now.year), 
                      month=options.get('month', now.month),
                      day=options.get('day', now.day),
                      hour=now.hour,
                      minute=now.minute,
                      second=now.second)

Answer 6

To set the stop_time, advance start_time one year, month or day as appropriate, then subtract one timedelta(microseconds=1)

if options['year']:
    start_time = start_time.replace(year=options['year'], month=1, day=1)
    stop_time = stop_time.replace(year=options['year']+1)-timedelta(microseconds=1)

elif options['month']:
    start_time = start_time.replace(month=options['month'], day=1)
    months=options['month']%12+1
    stop_time = stop_time.replace(month=months,day=1)-timedelta(microseconds=1)

else:
    start_time = start_time.replace(day=options['day'])
    stop_time = stop_time.replace(day=options['day'])+timedelta(days=1,microseconds=-1)