On Jun 3, 2011, at 16:59 , bjmjarrett wrote: > I am attempting to emulate the VLOOKUP function from Excel in R. > > I want to compare one column (coll.minus.release) with another > (release.days) to get the number of parasitoid released at that time > (TotalParasitoids). > > for example: > > coll.minus.release release.days ParasitoidTotal > -12 -266 1700 > 8 -259 1000 > 8 -225 1000 > 28 -216 1000 > 41 -28 1148 > 77 -12 1144 > 105 0 1160 > 105 8 972 > 125 28 1146 > 125 41 1004 > 125 77 1003 > 125 97 1010 > .... > 2772 NA NA > 2801 NA NA > 2834 NA NA > > > vlookup <- function(x) data[data$release.days==x,6] # as I have three other > columns that are not of interest > > vlookup(-12) = 1144, and so on, which is great. > > However, when I try: > > unlist(sapply(coll.minus.release,vlookup)) to apply it to the whole > coll.minus.release > > it works up to a point, as it doesn't give me 132 values for the 132 values > of coll.minus.release. Is this because the table of release.days and > TotalParasitoid has less values than coll.minus.release (108 compared to > 132)? To fill the gap I put in 0, and as none of the coll.minus.release > values = 0 I think it wouldn't affect it.
I wager that a look at setdiff(coll.minus.release,release.days) and vice versa would be illuminating. Notice that with your definition, vlookup(31415926) or any other number absent from release.days gives a zero-length vector. Presumably, you are looking for match(). > > Other things I have tried include findInterval and match. > > data[findInterval(x=data$coll.minus.release,vec=data$release.days,"ParasitoidTotal")] > > > didn't work as it said vec must be sorted non-decreasingly and didn't work > when I randomised the release.days and ParasitoidTotal columns as it doesn't > matter which order they are in. > > Thanks for reading all the way through - I wanted all the information I felt > you might need to help me in it. > > Any help will be greatly appreciated. > > -- > View this message in context: > http://r.789695.n4.nabble.com/VLOOKUP-in-R-tried-everything-tp3571107p3571107.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. -- Peter Dalgaard Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.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.
