try something like:
r$deltact[r$time == '0h'] <- 0
On Sat, May 29, 2010 at 7:50 PM, ANJAN PURKAYASTHA
<anjan.purkayastha at gmail.com> wrote:> 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 at 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.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?