'&&' is scalar 'and' you want to use the vector 'and' which is '&'.
On 30/05/2010 16:14, 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
-- Patrick Burns pbu...@pburns.seanet.com http://www.burns-stat.com (home of 'Some hints for the R beginner' and 'The R Inferno') ______________________________________________ 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.
