Tena koe Ken Would something along the following lines do what you require:
set.seed(1) x <- runif(100) y <- rep(NA, length(x)) y[x<0.25] <- -1 y[x>0.75] <- 1 y[-1][y[-length(y)]%in%1 & (x[-1]>=0.25 & x[-1]<0.5)] <- 0 # etc HTH .... Peter Alspach > -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Ken-JP > Sent: Saturday, 25 April 2009 12:16 p.m. > To: r-help@r-project.org > Subject: [R] How to get rid of loop? > > > set.seed(1) > x <- runif(100) > > # I want to calculate y such that: > # > # 1. if x>0.75, y <- 1 > # 2. else if x<0.25, y <- -1 > # 3. else if y_prev==1 && x<0.5, y <- 0 > # 4. else if y_prev==-1 && x>0.5, y <- 0 # 5. else y <- > y_prev # # 1. and 2. are directly doable without looping. > # > # How do I do 3.-5. without looping? The problem is, I need > to run this algorithm over gigs of data, so I # need to avoid > looping, if at all possible... > # > # - Ken > > > > -- > View this message in context: > http://www.nabble.com/How-to-get-rid-of-loop--tp23226779p23226779.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > The contents of this e-mail are confidential and may be subject to legal privilege. If you are not the intended recipient you must not use, disseminate, distribute or reproduce all or any part of this e-mail or attachments. If you have received this e-mail in error, please notify the sender and delete all material pertaining to this e-mail. Any opinion or views expressed in this e-mail are those of the individual sender and may not represent those of The New Zealand Institute for Plant and Food Research Limited. ______________________________________________ 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.
