Inclusive date ranges in python

Question

I didn't phrase this question correctly and as a result, none of the answers quite hit the mark.

What I wanted to know is, what's the best way to get time to return the end of a day in epoch milliseconds, if given just the date, rather than both date and time?

Here's how I'm doing it at the moment:

def get_epoch_endofday(day):
    return time.mktime(time.strptime('005923'+day,"%S%M%H%d%m%y"))*1000

The function takes the date in the form ddmmyy, and then spits out the epoch milliseconds on that day at 23:59:00.

I wondered, is there a more elegant way of doing this?

I'm not sure I understand what you want. Can you add an example of the kind of values you are looking for? What second date, why is `00:00` exclusive? — Martijn Pieters, Feb 08 '16 at 10:33
And if you are working with just dates, why not use `datetime.date()` objects? — Martijn Pieters, Feb 08 '16 at 10:34
More precisely what value should `day` have and what you expect as a return value from `get_epoch`. — Genti Saliu, Feb 08 '16 at 10:34
@MartijnPieters - Please see my edit. The dataset has the dates recorded in epoch miliseconds. — Charon, Feb 08 '16 at 10:42
@GentiSaliu - I've completely rephrased my question. Please let me know if you still need more context. — Charon, Feb 08 '16 at 11:08
You want to create an interval: beginning should be for eg. `2016-04-16 00:00:00`, end `2016-04-17 23:59:59`. Now you get for the end part `2016-04-17 00:00:00`, correct? — Genti Saliu, Feb 08 '16 at 11:13
The end of the interval should be on the same day, just 23 hours, 59 minutes, 59 seconds later? — Genti Saliu, Feb 08 '16 at 11:15
@GentiSaliu - It should be at the end of the day which I specify, yes. — Charon, Feb 08 '16 at 11:16
If any of the answers given below address your question, pease mark it as such, so that the thread is closed and removed from the board. Otherwise, please elaborate. Thanks. — Pouria, Feb 08 '16 at 12:01

score 2 · Answer 1 · edited May 23 '17 at 11:45

It wasn't very clear at first, but you want to create an interval for a given day (say 2016-02-14), which contains the first and last instant of that day. That means:

First instant: 2016-02-14 00:00:00.000

Last instant: 2016-02-14 23:59:59.999

The function below returns that interval as a tupel. It works like this:

create the start of the interval by creating a new date instance on the same day with hours, minutes and milliseconds all set to 0
create an interval spanning 23 hours, 59 minutes, 59 seconds and 999999 microseconds
add this interval to the beginning of the day

Code:

from datetime import datetime, timedelta

# 2016-02-08 11:39:31.093209
day = datetime.now()

def get_day_interval(day):
    start = datetime(day.year, day.month, day.day)
    interval = timedelta(seconds=59, microseconds=999999, minutes=59, hours=23)
    return (start, start + interval)

(start, end) = get_day_interval(day)

# 2016-02-08 00:00:00
print(start)

# 2016-02-08 23:59:59.999999
print(end)

Consult the Python docs for more options.

If the interval can be exclusive, the code becomes simpler, see the summary of this answer.

score 2 · Answer 2 · edited Jun 20 '20 at 09:12

Generators

Here is how you can create a function that produces an inclusive range:

def inc_range(stop, start=0, step=1):
    numerator = start

    while numerator<=stop:
        yield numerator
        numerator += step


a = [val for val in inc_range(10)]
print(a)

Displays:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Now this method can be adapted for anything you want; date or otherwise.

Date range generator

Here it the method tailored to your needs:

from datetime import date, timedelta 


def date_range(stop, start, step=1):
    delta_date = stop - start
    numerator = 0

    while numerator <= delta_date.days:
        yield str(start + timedelta(numerator))
        numerator += step


date_start = date(2014, 3, 15)
date_end = date(2014, 3, 21)

a = [val for val in date_range(date_end, date_start)]
print(a)

Displays:

['2014-03-15', '2014-03-16', '2014-03-17', '2014-03-18', '2014-03-19', '2014-03-20', '2014-03-21']

Note that if you don't include str() when yielding in the generator, the response would be an object of datetime.date() instead.

Hope this answers your question.

Inclusive date ranges in python

2 Answers2

Generators

Date range generator