I just noticed something by accident with R syntax that I'm sure is correct but I don't understand it. If I have a simple numeric vector x and I subscript it, it seems that I can then subscript a second time with TRUE or FALSE, sort of like a 2 dimensional array in C. Does someone know if this is documented somewhere Because it's neat but I never knew it existed. To me it seems like a 1 dimensional vector should have only one dimensional indexing ?
x <- seq(1,10) > x [1] 1 2 3 4 5 6 7 8 9 10 > x[2:4][c(TRUE,FALSE,TRUE)] [1] 2 4 But, it only works for TRUE or FALSE and not numbers so I think it's not really 2 dimensional indexing. x[1][2] [1] NA If someone could explain this mechanism or tell me what I should look for in the archives, it would be appreciated. Thanks. -------------------------------------------------------- This is not an offer (or solicitation of an offer) to bu...{{dropped:22}} ______________________________________________ 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.