If I have two dates (ex. '8/18/2008' and '9/26/2008'), what is the best way to get the number of days between these two dates?
If you have two date objects, you can just subtract them, which computes a timedelta object.
from datetime import date
d0 = date(2008, 8, 18)
d1 = date(2008, 9, 26)
delta = d1 - d0
print(delta.days)
The relevant section of the docs: https://docs.python.org/library/datetime.html.
See this answer for another example.