Hi, I have a data-frame r (shown below is a subset) with the following column names: date time sample vct norm hct deltact
$time has 8 levels: 0h, 0.5h, .....24h. $deltact holds real numbers. I want to subset this dataframe by the levels of $time. For all the rows which have r$time == "0h" I would like to convert the present value of r$deltact to 0. Any pointers to a simple method to accomplish would be greatly appreciated. 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.