Hi, You could try this: (if I understand it correctly) dat1<- read.table(text=" year id var ans 2010 1 1 1 2010 2 0 0 2010 1 0 1 2010 1 0 1 2011 2 1 1 2011 2 0 1 2011 1 0 0 2011 1 0 0 ",sep="",header=TRUE,stringsAsFactors=FALSE)
dat1$newres<-with(dat1,ave(var,id,year,FUN=function(x) any(x==1)*1)) dat1 # year id var ans newres #1 2010 1 1 1 1 #2 2010 2 0 0 0 #3 2010 1 0 1 1 #4 2010 1 0 1 1 #5 2011 2 1 1 1 #6 2011 2 0 1 1 #7 2011 1 0 0 0 #8 2011 1 0 0 0 A.K. ----- Original Message ----- From: Anup Nandialath <anupme...@gmail.com> To: r-help@r-project.org Cc: Sent: Sunday, July 14, 2013 7:30 AM Subject: [R] creating dummy variables based on conditions Hello everyone, I have a dataset which includes the first three variables from the demo data below (year, id and var). I need to create the new variable ans as follows If var=1, then for each year (where var=1), i need to create a new dummy ans which takes the value of 1 for all corresponding id's where an instance of one was recorded. Sample data with the output is shown below. year id var ans [1,] 2010 1 1 1 [2,] 2010 2 0 0 [3,] 2010 1 0 1 [4,] 2010 1 0 1 [5,] 2011 2 1 1 [6,] 2011 2 0 1 [7,] 2011 1 0 0 [8,] 2011 1 0 0 Any help on how to achieve this is much appreciated. Thanks Anup [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
