thanks for the help up to here. A little problem remains.
I have different "ABNR", if i try it with another ABNR, the Column extend for each ABNR, it should start with "FIRST" again. dat1 <- read.table(text="FS_ID ABNR 9327 33688812 11391 33688812 11392 33688812 11388 33688812 11390 33688812 12028 33688812 12029 33688812 19999 33800000",sep="",header=TRUE) dat2 <- read.table(text="FS_ID DATE POST 11390 2012-12-13 28 12029 2013-01-17 28.3 11391 2011-02-20 29 19999 2014-02-20 10",header=TRUE,stringsAsFactors=FALSE) library(reshape2) setNames(dcast(merge(dat1,dat2, by="FS_ID")[,-1],ABNR~DATE,value.var="POST"),c("ABNR","FIRST","SECOND")) ABNR FIRST SECOND THREE NA 1 33688812 29 28 28.3 NA 2 33800000 NA NA NA 10 it shoult start for each ABNR in the "FIRST"-Column again. Right would be: ABNR FIRST SECOND THREE 1 33688812 29 28 28.3 2 33800000 10 NA NA Thank you. -- View this message in context: http://r.789695.n4.nabble.com/combine-2-data-frames-in-dependence-of-the-ID-tp4685781p4685855.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.