CODEWITHSUNDEEP
pythondatetime
Malte Susen
Malte Susen

Reputation: 845

Python: Increasing Dates with each Loop

For a current project, I am planning to increase the value of a calendar date by 3 months with each iteration/loop. The value for start_date should hence be [1st iteration]: 01/01/2017, [2nd interation] 01/04/2017 etc. For end_date, it should accordingly yield [1st iteration]: 31/03/2017, [2nd interation] 30/06/2017 etc.

I originally thought it would be a simple point to solve but somehow the script is not working as planned (also as many threads discuss how to increase values in one go but not how to perform this in several loops). Does anyone know how to tweak things?

The corresponding code looks as follows:

import datetime
from dateutil.relativedelta import *

for i in df.iterrows():
    start_date = '01/01/2017'
    start_date = start_date + relativedelta(months=+3)
    end_date = '31/03/2017'
    end_date = end_date + relativedelta(months=+3)

    print(start_date)
    print(end_date)

Upvotes: 0

Views: 283

Answers (1)

David
David

Reputation: 1202

Your problem is that you are initialising the start_date and end_date inside the loop. Just initialise them once outside the loop, then continue process like you're doing.

import datetime
from dateutil.relativedelta import *

# year, month, day
start_date = datetime.date(2017, 1, 1)
end_date = datetime.date(2017, 3, 31)

for i in df.iterrows():
    start_date += relativedelta(months=3)
    end_date += relativedelta(months=3)

    print(start_date)
    print(end_date)

Upvotes: 1

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