residuals[abs(residuals) > (2*sd)]
gcm <lvog...@grahamcapital.com> wrote on 07/16/2012 07:07:31 AM: > Jean, how would you modify your function to grab all the selected > and not just the first? > Thank you so much! > > From: Jean V Adams [via R] [ mailto:ml-node+s789695n4636370...@n4.nabble.com] > Sent: Thursday, July 12, 2012 4:59 PM > To: Lauren Vogric > Subject: Re: Grabbing Indexes of a certain standard deviation > > I wrote a little function called first() to help with situations like > this. It returns a 1 every time an element of a vector is different from > the previous element, and a 0 otherwise. > > first <- function(x) { > L <- length(x) > c(1, 1-(x[-1]==x[-L])) > } > > sd <- 1 > residuals <- c(1, 2.1, 3, 4, 3, 1, 0, -4, -1) > # logical, indicating if the residual exceeds 2 standard deviations > exceed <- abs(residuals) > (2*sd) > # indices of the first exceeding residual of a series > which(first(exceed) & exceed) > > Jean > > > gcm <[hidden email]</user/SendEmail.jtp?type=node&node=4636370&i=0>> > wrote on 07/12/2012 11:07:49 AM: > > > I have a graph of residuals and I am attempting to get a list of the > indexes > > of each time the residual is greater than 2 standard deviations or less > than > > -2 standard deviations, but only the first point of the section. And > then > > I'd also need the first point where the point returns to the range > between > > +/- 2 standard deviations. > > So basically if my standard deviation=1 and my residuals=c(1, 2.1, 3, 4, > 3, > > 1, 0, -4, -1) I want it to grab the second number, where it exceeds 2 > > standard deviations and the 6th where it returns to less than 2 standard > > deviations. Also, it would grab -4 (or residuals[ 8]) and -1 > (residuals[9]) [[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.
