Reading Dates/Times from a SAS file: read_sas vs. read.SAS7bdat

Question

I am trying to replace the read.SAS7bdat function with read_sas from the haven package in a number of my programs due to speed. Simply substituting it in works perfectly and reads so much quicker. However, the only hang-up I encounter has to deal with dates and times. For some reason, I can no longer subset by a date selected in an R Shiny date input even though the underlying data looks the same and all other functions work. If anyone knows of a difference between how these two functions read dates that would be greatly appreciated.

Answer 1

Date zero in SAS is 1 Jan 1960, and in R (origin date) it is 1 Jan 1970. That might be the reason for your issue. Bring in dates as character from SAS, and then convert it to numeric in R.

Answer 2

There were two components: first I had to change the origin date to 1970 instead of 1960 as I previously was using with read.sas7bdat. I also had previously converted everything to a POSIX date, which worked fine. However, subsetting by an R shiny date input wasn't working with read_sas so I converted the posix using as.date and this resolved it. Not exactly sure why though.