My Coyne wrote: > Hello, > > > > Newbie question and hope you can help . > > I have two vector V1 and V2, where length(V2) = length of (V1) * 2; > length(V1) ~ 16,000. > > For each member in V1, I need to compare 2 element of V2 for equality
If just the comparison is concerned, you can do it in vectorized form, but I am not sure of you want to comapre v1[i] with v2[i] and v2[i+1], otherwise it would not make sense that length(V2) = length of (V1) * 2 ... Say length(V1) is n, do you want to compare v1[1] with v2[1] and v2[2] and v1[2] with v2[3] and v2[4] or v1[1] with v2[1] and v2[n+1] and v1[2] with v2[2] and v2[n+2] ??? Uwe Ligges > > > i.e. > > for (I in 1:length (V1)) { > > if ( v2[i] == v1[i] & v2[i+1]==v1[i] ){ > > statement_1 > > statement_2 > > . > > } > > } > > > > This for-loop is too slow (it takes a good 5 minutes on my Windows machine) > to finish processing the vector V1 of 16,000; I will need to process a lot > more than 16,000 (about 300*16,000). > > > > Is there a better way to do looping with R? Any help is greatly appreciate > > > > --MyC. > > > > > > > > > > > > > > > > > [[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. ______________________________________________ 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.