Split days between 2 given dates into specific batch size and get the start and end_date accordingly

Question

I want to split the days between 2 given dates into a specific batch size to make my api call easy. I am currently using this to split it on a monthly basis. However, need to split it further depending on user input batch size and get the start and end_date.

For eg:

start_date : 2020-01-01
end_date : 2020-01-31
batch: 10

Output:

start: 2020-01-01
end :2020-01-10

start : 2020-01-11
end: 2020-01-20

start : 2020-01-21
end: 2020-01-30

start: 2020-01-31
end: 2020-01-31

I am doing this: what changes should I make?

from dateutil import rrule, parser
start = parser.parse('Jan 21 2020')
end   = parser.parse('Oct 30 2020')
date_list = [start]
date_list.extend(list(rrule.rrule(rrule.MONTHLY, bymonthday=(-1,1), dtstart=start, until=end)))
date_list.append(end)
print(date_list)

Answer 1

You can use the datetime and timedelta option to get the batches. You don't need to load dateutil and do complex manipulation. datetime already has the ability to compute dates like numbers. Use the available function in datetime.

import datetime
start_date = '2020-01-01'
end_date = '2020-01-31'
batch = 10

#First convert the string version of start and end dates into datetime

start = datetime.datetime.strptime(start_date, '%Y-%m-%d')
end = datetime.datetime.strptime(end_date, '%Y-%m-%d')

#then set the timedelta to the batch - 1 day
#end date is always calculated as 9 more days not 10 (hence -1)

step = datetime.timedelta(days=(batch-1))

#iterate through the loop until start <= end

while start <= end:
    print ('Start :', start.date())    #print start date
    start += step                      #add the timedelta to start
    if start > end: start = end
    print ('End :', start.date())      #print end date
    start += datetime.timedelta(days=1)  #now increment by 1 more to get start date
    print ()

The output of this will be:

Start : 2020-01-01
End : 2020-01-10

Start : 2020-01-11
End : 2020-01-20

Start : 2020-01-21
End : 2020-01-30

Start : 2020-01-31
End : 2020-01-31