Convert two datetime objects to monthly datetime range

Question

I have two datetime objects, let's say start_date and end_date. What I want to do is to make a list of datetime objects.

>>> from datetime import datetime
>>> from dateutil.rrule import rrule, MONTHLY
>>> start_date = datetime(2018, 9, 6, 0,)
>>> end_date = datetime(2018, 11, 26, 23, 59, 59)
>>> list(rrule(MONTHLY, dtstart=start_date, until=end_date))
[datetime.datetime(2018, 9, 6, 0, 0), datetime.datetime(2018, 10, 6, 0, 0), datetime.datetime(2018, 11, 6, 0, 0)]

I can do this with rrule(), it's moving from date to date but I want it to go month-wise and also include the end_date,

[
    datetime.datetime(2018,9,6,0,0), 
    datetime.datetime(2018,9,30,23,59),
    datetime.datetime(2018,10,1,0,0),
    datetime.datetime(2018,10,31,23,59),
    datetime.datetime(2018,11,1,0,0),
    datetime.datetime(2018,11,26,23,59)
]

I would prefer to do this without using pandas or numpy.

Haven't you already got that as the result in your first code block... I'm not clear what that second code block showing a list of datetimes is for here? — Jon Clements, Nov 26 '18 at 14:30
@JonClements I guess the OP is looking for a list with start_date and end_date for every month. I do agree with you that the question is not very clear. — rpanai, Nov 26 '18 at 14:32
I guess that you can figure out a solution using [this](https://stackoverflow.com/questions/42950/get-last-day-of-the-month-in-python) — rpanai, Nov 26 '18 at 14:35
@JonClements I want to go from start_date to end_date month by month, not a 30 days jump. — Sadan A., Nov 26 '18 at 15:28

Franco Pettigrosso · Answer 1 · 2018-11-26T14:56:33.473

0

here's how you can get a list of dates between two ranges. you can modify it to add certain dates.

from datetime import datetime
from datetime import timedelta
import calendar
dates = []

start_date = datetime(2018, 9, 6, 0,)
end_date = datetime(2018, 10, 10, 0,)
index_date = start_date
while True:
    index_date = index_date
    dates.append(index_date)
    dayy = calendar.monthrange(index_date.year,index_date.month)
    index_date = index_date.replace(day= dayy[1])
    if  index_date > end_date:
        break
    dates.append(index_date)
    index_date = index_date + timedelta(days=1)
    if  index_date > end_date:
        break
print dates

edited Nov 26 '18 at 14:56

answered Nov 26 '18 at 14:36

Franco Pettigrosso

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Yes, but the OP wants *"MONTHLY"*, edit your Answer ans show the output – stovfl Nov 26 '18 at 14:38
I think this is what you want. here you don't need any functions, pandas, or anything. just the vanilla datetime and calendar. – Franco Pettigrosso Nov 26 '18 at 15:00

score 0 · Answer 2 · answered Nov 26 '18 at 14:39

Try this

import datetime

def last_day_of_month(date):
    if date.month == 12:
        return date.replace(day=31)
    return date.replace(month=date.month+1, day=1) - datetime.timedelta(days=1)


def desired_output(start_date,end_date):
    curr_date = start_date
    desired_list = []
    desired_list.append(start_date)
    while curr_date<=end_date:
        if last_day_of_month(curr_date)>end_date:
            desired_list.append(end_date)
            break
        desired_list.append(last_day_of_month(curr_date))
        curr_date = last_day_of_month(curr_date) + datetime.timedelta(1)
        if curr_date<end_date:
            desired_list.append(curr_date)
        else:
            break
    return desired_list

print(desired_output(datetime.datetime(2018,9,6,0,0), datetime.datetime(2018,12,26,0,0)))

Convert two datetime objects to monthly datetime range

2 Answers2