Dear anonymous: 1. You may be more likely to get "useful tips" on this list if you sign with your real name. It's friendlier.
2. If you are using R "14 hours/day." get and read a good R book. The CRAN site or Amazon lists many; choose one or more that suits your needs. 3. Read the R Help files carefully. ?lm tells you that you do not need a loop to fit many y's simultaneously: "If response is a matrix a linear model is fitted separately by least-squares to each column of the matrix. " 4. Loops are not necessarily so terrible. "apply" type functions are basically loops, also; their chief advantage is often just code readability, not efficiency. 5. For tasks such as yours, ?update methods are typically useful. Cheers, Bert On Mon, Dec 26, 2011 at 4:29 AM, iliketurtles <[email protected]> wrote: > Hi, I'm quite new to R (1 month full time use so far). I have to run loop > regressions VERY often in my work, so I would appreciate some new > methodology that I'm not considering. > > #--------------------------------------------------------------------------------------------- > y<-matrix(rnorm(100),ncol=10,nrow=10) > x<-matrix(rnorm(50),ncol=5,nrow=10) > > #Suppose I want to run the specification y=A+Bx+error, for each and every > y[,n] onto each and every x[,n]. > #So with: > ncol(y);ncol(x) > #I should end up with 10*5=50 regressions in total. > > #I know how to do this fine: > MISC1<-0 > for(i in 1:ncol(y)){ > for(j in 1:ncol(x)){ > reg<-lm(y[,i]~x[,j]) > MISC1<-cbind(MISC1,coef(reg)) #for coefficients > }} > coef<-matrix(MISC1[,-1],ncol=50) > > coef[,1];coef(lm(y[,1]~x[,1])) #test passed > ncol(coef) #as desired, 50 regressions. > #--------------------------------------------------------------------------------------------- > > Now for my question: Is there easier or better methods of doing this? I know > of a lapply method, but the only lapply way I know of for lm(..) is > basically doing a lapply inside of a lapply, meaning it's exactly the same > as the double loop above... I'm looking to escape from loops. > > Also, if any of you could share your top R tips that you've learned over the > years, I'd really appreciate it. Tiny things like learning that array() and > matrix() can have a 3rd dimension, learning of strsplit, etc.. have helped > me immeasurably. (Not that I'm also googling for this stuff! I'm doing R 14 > hours a day!). > > Thanks. > > -- > View this message in context: > http://r.789695.n4.nabble.com/Other-ways-to-lm-regression-non-loop-tp4234487p4234487.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > [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. -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ [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.
