Re: [R] Can you have a by variable in Lag function as in SAS

Thank you again all responders. Dan your solution was both easy & miraculous. -- View this message in context: http://r.789695.n4.nabble.com/Can-you-have-a-by-variable-in-Lag-function-as-in-SAS-tp4649647p4649773.html Sent from the R help mailing list archive at Nabble.com.

Re: [R] Can you have a by variable in Lag function as in SAS

Hi Ramoss, There are a few solutions to this - probably the best solution involves proper handling of time series/date objects. But, for "an" answer try: # Build a data frame ... set.seed(123) someTimes <- sapply(1:5, function(i) sort(round(runif(6, 0, 24 myDf <- data.frame(Day = rep(1:5, ea

Re: [R] Can you have a by variable in Lag function as in SAS

> -Original Message- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of ramoss > Sent: Thursday, November 15, 2012 11:56 AM > To: r-help@r-project.org > Subject: [R] Can you have a by variable in Lag function as in SAS > > H

[R] Can you have a by variable in Lag function as in SAS

Hello, I want to use lag on a time variable but I have to take date into consideration ie I don't want days to overlap ie: I don't want my first time of today to match my last time of yeterday. In SAS I would use : data x; set y; by date tim; previous=lag(tim); if first.date then d