R/intertomain.R

In RAMP: Regularized Generalized Linear Models with Interaction Effects

intertomain <- function(interNameList, p) {
    ### convert an interaction name list into the corresponding main effect for
    ### enforcing strong hierachy.  input: interNameList: interaction name list input:
    ### p: dimensionality
    mainInd = rep(0, p)
    for (i in 1:length(interNameList)) {
        interName = interNameList[[i]]
        pair = as.numeric(strsplit(interName, "X")[[1]][2:3])
        mainInd[pair[1]] = 1
        mainInd[pair[2]] = 1
    }
    return(which(mainInd == 1))
}