Genius, That certainly is much faster that what I had worked out on my own.
I looked at sweep, but couldn't understand the rather thin help page. Your example makes it really clear Thank You!!! -- Noah On 9/11/09 1:57 PM, Gavin Simpson wrote: > On Fri, 2009-09-11 at 13:10 -0700, Noah Silverman wrote: > >> Hi, >> >> Is there an alternative to the scale function where I can specify my own >> mean and standard deviation? >> > A couple of calls to sweep? > > See ?sweep > > set.seed(123) > dat<- data.frame(matrix(runif(10*10), ncol = 10)) > xbar<- colMeans(dat) > sigma<- apply(dat, 2, sd) > > dat.std<- sweep(sweep(dat, 2, xbar, "-"), 2, sigma, "/") > > ## compare > scale(dat) > > HTH > > >> I've come across an interesting issue where this would help. >> >> I'm training and testing on completely different sets of data. The >> testing set is smaller than the training set. >> >> Using the standard scale function of R seems to introduce some error. >> Since it scales data WITHIN the set, it may scale the same number to >> different value since the range in the training and testing set may be >> different. >> >> My thought was to scale the larger training set of data, then use the >> mean and SD of the training data to scale the testing data according to >> the same parameters. That way a number will transform to the same >> result regardless of whether it is in the training or testing set. >> >> I can't be the first one to have looked at this. Does anyone know of a >> function in R or if there is a scale alternative where I can control the >> parameters? >> >> Thanks! >> >> -- >> Noah >> >> ______________________________________________ >> 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. >> [[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.
