If you want integers don't use strftime

Pontifications

If you want integer values don’t use something that returns strings :-) and then cast (or rely on casting) them to integers.
In particular don’t use strftime to get the integer day of the year like I did originally in addDayOfTheyYear.rb instead use the integer API e.g. in addDayOfTheyYear.rb :

t = Time.at(row[1].to_i)
s = t.yday #not strftime !!!!!
year = t.year #not strftime !!!!!!!!!