try t <- subset(r, (r$time == "0h" & r$strain == "ROC"), select= c(time,strain, gene, deltact)) Do ?"&" to understand the difference between & and && .
ANJAN PURKAYASTHA wrote: > > Hi, > I have a data-frame, r (column names below), that needs subsetting: > date, time, strain, gene, deltact > > When I try to subset r by applying selection criteria on two columns I get > an empty data frame. For example I would like to extract all rows that > have > time == 0h and strain == ROC. > So, t <- subset(r, (r$time == "0h" && r$strain == "ROC"), select= c(time, > strain, gene, deltact)) returns an empty data-frame. > Is it not possible to subset based on two criteria? > TIA > Anjan > > -- > =================================== > anjan purkayastha, phd. > research associate > fas center for systems biology, > harvard university > 52 oxford street > cambridge ma > phone-703.740.6939 > =================================== > > [[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. > > -- View this message in context: http://r.789695.n4.nabble.com/subsetting-tp2236334p2236388.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.