Larry White wrote: > > Sorry - this must be obvious, > Yes, it is :-)
> I want to be able to filter data in a dataframe before analyzing it. > For example, I'd like to plot(a,b) but only include values where b > > 1000. > If a and b are vectors, then b > 1000 is another vector of logical values. You can use logical vectors to select pieces of other vectors, like this: x <- c(1, 2, 3) y <- c(TRUE, FALSE, FALSE) x[y] # returns only the first element, 1 So, this plot can be done this way: filter <- (b > 1000) # filter is a logical vector a1 <- a[filter] b1 <- b[filter] # Now, a1 and b1 are, resp, a and b filtered plot(a1, b1) Alberto Monteiro ______________________________________________ [email protected] 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.
