Python> datetime> Implementation> Specify the end date, interval, and start date, and return and display each interval.

Operation check

Python 3 (ideone)

Implement the following.

--Start from the end date --Return the date every interval --Displays the date beyond the start date and stops

It seems to use timedelta () of datetime. https://docs.python.jp/3/library/datetime.html

code

http://ideone.com/maiFmH

from datetime import datetime as dt
from datetime import timedelta

ENDSTR = "20170202"
STARTSTR = "20161031"
INTERVAL_DAY = 13

enddt = dt.strptime(ENDSTR, '%Y%m%d')
startdt = dt.strptime(STARTSTR, '%Y%m%d')

wrkdt = enddt
while True:
    print(wrkdt)
    if wrkdt < startdt:
        break
    wrkdt = wrkdt + timedelta(days=-INTERVAL_DAY)

run

2017-02-02 00:00:00
2017-01-20 00:00:00
2017-01-07 00:00:00
2016-12-25 00:00:00
2016-12-12 00:00:00
2016-11-29 00:00:00
2016-11-16 00:00:00
2016-11-03 00:00:00
2016-10-21 00:00:00