Dear R users, I'm new in R and couldn't find the solution to this in the postings. I want to be able to use the "leaps" package to perform an "exhaustive" regression. Most of my variables are categorical with many levels. I'd like to restrict the candidate subsets to either all levels included or all excluded in the list. Here's the current and desired output from a dummy example: #Generate random data y <- rnorm(n=1000, mean=100, sd=10) #normal distribution a <- gl(n=4, k=1, length=1000, label=c("F1", "F2", "F3", "F4")) b <- gl(n=4, k=3, length=1000, label=c("G1", "G2", "G3", "G4")) mydata <- data.frame(y, a, b) require("leaps") subsets <- regsubsets(y ~ . , data=mydata, method="exhaustive") subsets subset.models <- summary(subsets)$which subset.models (Intercept) aF2 aF3 aF4 bG2 bG3 bG4 1 TRUE FALSE FALSE FALSE TRUE FALSE FALSE 2 TRUE FALSE FALSE FALSE TRUE FALSE TRUE 3 TRUE FALSE FALSE FALSE TRUE TRUE TRUE 4 TRUE FALSE TRUE FALSE TRUE TRUE TRUE 5 TRUE TRUE TRUE FALSE TRUE TRUE TRUE 6 TRUE TRUE TRUE TRUE TRUE TRUE TRUE My desired output is: (Intercept) aF2 aF3 aF4 bG2 bG3 bG4 3 TRUE FALSE FALSE FALSE TRUE TRUE TRUE 3 TRUE TRUE TRUE TRUE FALSE FALSE FALSE 6 TRUE TRUE TRUE TRUE TRUE TRUE TRUE Thanks in advance for your help. Axel. [[alternative HTML version deleted]]