How to display all the months between given two dates?

Question

I am trying to generate list of months between two dates. For Example:

startDate = '2016-1-31'
endDate = '2017-3-26'

It should result as:

datetime.date(2016, 1, 31)
datetime.date(2016, 2, 28)
and so on....

I am trying like this

startDate = '2016-1-28'
endDate = '2017-3-26'

start = date(*map(int, startDate.split('-')))
end = date(*map(int, endDate.split('-')))

week = start
dateData = []

while week <= end:
    dateData.append(week)
    week = week + datetime.timedelta(weeks=4)

pprint(dateData)

This gives result as:

[datetime.date(2016, 1, 31),
 datetime.date(2016, 2, 28),
 datetime.date(2016, 3, 27),
 datetime.date(2016, 4, 24),
 datetime.date(2016, 5, 22),
 datetime.date(2016, 6, 19),
 datetime.date(2016, 7, 17),
 datetime.date(2016, 8, 14),
 datetime.date(2016, 9, 11),
 datetime.date(2016, 10, 9),
 datetime.date(2016, 11, 6),
 datetime.date(2016, 12, 4),
 datetime.date(2017, 1, 1),
 datetime.date(2017, 1, 29),
 datetime.date(2017, 2, 26),
 datetime.date(2017, 3, 26)]

Here "2016, 12" & "2017, 1" is repeating twice. Can anybody help me solve this problem.

Answer 1

You could use the dateutil extension's relativedelta method like below -

from datetime import datetime
from dateutil.relativedelta import relativedelta

startDate = '2016-1-28'
endDate = '2017-3-26'

cur_date = start = datetime.strptime(startDate, '%Y-%m-%d').date()
end = datetime.strptime(endDate, '%Y-%m-%d').date()

while cur_date < end:
    print(cur_date)
    cur_date += relativedelta(months=1)

Following is the output

2016-01-28
2016-02-28
2016-03-28
2016-04-28
2016-05-28
2016-06-28
2016-07-28
2016-08-28
2016-09-28
2016-10-28
2016-11-28
2016-12-28
2017-01-28
2017-02-28

Answer 2

You can also use only pandas in one line:

import pandas as pd
pd.date_range('2018-01', '2020-05', freq='M')

The output will be:

DatetimeIndex(['2018-01-31', '2018-02-28', '2018-03-31', '2018-04-30',
           '2018-05-31', '2018-06-30', '2018-07-31', '2018-08-31',
           '2018-09-30', '2018-10-31', '2018-11-30', '2018-12-31',
           '2019-01-31', '2019-02-28', '2019-03-31', '2019-04-30',
           '2019-05-31', '2019-06-30', '2019-07-31', '2019-08-31',
           '2019-09-30', '2019-10-31', '2019-11-30', '2019-12-31',
           '2020-01-31', '2020-02-29', '2020-03-31', '2020-04-30'],
          dtype='datetime64[ns]', freq='M')