Thank you Florent, it really helps. Regards, Jorge.-
On Thu, Jan 19, 2012 at 7:28 PM, Florent D. <> wrote: > Another possibility: > > df$Date[match(1800, df$myvalue)] > > match() stops at the first value encountered so it may be a bit faster > than a full subset(), depending on your table size. > Another difference: this approach would return NA if there was no > match, subset(...)[1, ] would trigger an error. Depends what your > needs are. > > On Thu, Jan 19, 2012 at 7:03 PM, Jorge I Velez <> wrote: > > Hi ikuzar, > > > > Try > > > > subset(df, myvalue == 1800, select = Date)[1, ] > > > > See ?subset for more information. > > > > HTH, > > Jorge.- > > > > > > On Thu, Jan 19, 2012 at 6:42 PM, ikuzar <> wrote: > > > >> Hi, > >> I 'd like to select the Date where myvalue =1800 appears the* first > time*. > >> > >> For instance: > >> df =data.frame(date, myvalue, ...) > >> > >> ... > >> > >> Date myvalue > >> 2012-01-05 2500 > >> 2012-01-06 2450 > >> *2012-01-07 1800* > >> 2012-01-08 2200 > >> 2012-01-09 1800 > >> > >> I'd like to retrieve the third line. > >> > >> I do not find a clean way. > >> > >> Thanks for your help > >> > >> > >> > >> -- > >> View this message in context: > >> > http://r.789695.n4.nabble.com/dataframe-how-to-select-an-element-from-a-row-tp4311881p4311881.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. > >> > > > > [[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. > [[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.
