On Apr 6, 2015, at 1:56 PM, Keshav Dhandhania wrote: > Hi, > > I know that one can find all occurrences of x in a vector v by doing >> which(x == v). > > However, if I need to do this again and again, where v is remaining the > same, then this is quite inefficient. In my particular case, I need to do > this millions of times, and length(v) = 100 million. > > Does anyone have suggestion on how to go about it? > I know of a package called fmatch that does the above for the match > function. But they don't handle multiple matches. >
You should explain why you need to do it millions of times and you should pose a small sample problem that presents the level of complexity needed in a minimal size. > Thanks > > [[alternative HTML version deleted]] And you should read the Posting Guide where it is strongly advised that you not post in HTML format. I have used gmail and I do know that it is fairly easy to post in plain text. -- David Winsemius Alameda, CA, USA ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
