How do I find missing dates in a list of sorted dates?

Question

In Python how do I find all the missing days in a sorted list of dates?

Answer 1

USING A FOR LOOP

The imports you'll need:

import datetime
from datetime import date, timedelta

Let's say you have a sorted list called dates with several missing dates in it.

First select the first and last date:

start_date = dates[0]
end_date = dates[len(dates)-1]

Than count the number of days between these two dates:

numdays = (end_date - start_date).days

Than create a new list with all dates between start_date and end_date:

all_dates = []
for x in range (0, (numdays+1)):
all_dates.append(start_date + datetime.timedelta(days = x))

Than check with dates are in all_dates but not in dates by using a for loop with range and adding these dates to dates_missing:

dates_missing = []

for i in range (0, len(all_dates)):
   if (all_dates[i] not in dates):
       dates_missing.append(all_dates[i])
   else:
       pass

Now you'll have a list called dates_missing with all the missing dates.