thanks Michael. I played with your suggestion to get the output in the format I wanted, and I found the following that works fine:
sub<-d[, which(colnames(d) %in% v) ] Aurelien 2011/12/2 R. Michael Weylandt <michael.weyla...@gmail.com> < michael.weyla...@gmail.com> > How about this? > > d[, v[v %in% colnames(d)]] > > Michael > > On Dec 2, 2011, at 12:01 PM, Aurélien PHILIPPOT < > aurelien.philip...@gmail.com> wrote: > > > Hi Paul and Jim, > > Thanks for your messages. > > > > I just wanted R to give me the columns of my data frame d, whose names > > appear in v. I do not care about the names of v that are not in d. In > > addition, every time, there will be at least one element of v that has a > > corresponding column in d, for sure, so I know there is at least one > match > > between the 2. > > > > Initially, I tried something in the spirit: > > sub<- subset(d, colnames(d) %in% v) > > > > but I could not make it work properly. > > > > > > Best, > > Aurelien > > > > 2011/12/2 Paul Hiemstra <paul.hiems...@knmi.nl> > > > >> On 12/02/2011 07:20 AM, Aur�lien PHILIPPOT wrote: > >>> Dear R-users, > >>> -I am new to R, and I am struggling with the following problem. > >>> > >>> -I am repeating the following operations hundreds of times, within a > >> loop: > >>> I want to subset a data frame by columns. I am interested in the > columns > >>> names that are given by the rows of another data frame that was built > in > >>> parallel. The solution I have so far works well as long as the elements > >> of > >>> the second data frame are included in the column names of the first > data > >>> frame but if an element from the second object is not a column name of > >> the > >>> first one, then it bugs. > >> > >> Hi Aurelien, > >> > >> I would call this a feature, not a bug. I think R does what it should > >> do, you request a non-existent column and it throws an error. What kind > >> of behavior are you looking for instead of this error? > >> > >> regards, > >> Paul > >> > >>> > >>> -More concretely, I have the following data frames d and v: > >>> yyyymmdd<-c("19720601", "19720602", "19720605") > >>> sret.10006<-c(1,2,3) > >>> sret.10014<-c(5,9,7) > >>> sret.10065<-c(10,2,11) > >>> > >>> > >>> d<- data.frame(yyyymmdd=yyyymmdd, sret.10006=sret.10006, > >>> sret.10014=sret.10014, sret.10065=sret.10065) > >>> > >>> v<- data.frame(V1="sret.10006", V2="sret.10090") > >>> v<- sapply(v, function(x) levels(x)[x]) > >>> > >>> -I want to do the following subsetting: > >>> sub<- subset(d, select=c(v)) > >>> > >>> > >>> and I get the following error message: > >>> Error in `[.data.frame`(x, r, vars, drop = drop) : > >>> undefined columns selected > >>> > >>> > >>> > >>> Any help would be very much appreciated, > >>> > >>> Best, > >>> Aurelien > >>> > >>> [[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. > >> > >> > >> -- > >> Paul Hiemstra, Ph.D. > >> Global Climate Division > >> Royal Netherlands Meteorological Institute (KNMI) > >> Wilhelminalaan 10 | 3732 GK | De Bilt | Kamer B 3.39 > >> P.O. Box 201 | 3730 AE | De Bilt > >> tel: +31 30 2206 494 > >> > >> http://intamap.geo.uu.nl/~paul > >> http://nl.linkedin.com/pub/paul-hiemstra/20/30b/770 > >> > >> > > > > [[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.