How do I convert date to number of days in R

Question

How do I convert date to number of days, starting from the first day of the year.

How do I convert the following to the expected result below?

   Dat         


        

Answer 1

I guess this will help:

Use as.Date()

Example:

one <- as.Date(c("02/01/2000", "01/01/2000"))

number of days between 02/01/2000 and 02/01/2000:

days <- one[1] - one[2]