[R] Advice requested: Best method of coding "time since" repeating event

[M-J S Milloy]

Hello,

I have a dataset containing approx 1000 events spanning four years (2004.03 to 2008.07). For each event, I'd like to determine the time (in minutes) since the most recent final Wednesday of the month. I've found no obvious solution on the list or online; I think I'll try to use functions in the chron package. 

Anyone have any other advice?

Thanks.


M-J


School of Population and Public Health,
University of British Columbia
Vancouver, Canada

Centre for Excellence in HIV/AIDS,
St. Paul's Hospital
Vancouver, Canada