R/variablelist.R

In forsearch: Diagnostic Analysis Using Forward Search Procedure for Various Models

variablelist <-
function(datadf, prank)
{
     #                          variablelist
     #
     # VALUE     List of 2-column matrices, each of which is a level of the level1 * level2 * level3 * . . . 
     #               possible levels of the character variables
     #
     # INPUT          datadf     Data frame of independent variables in analysis
     #                prank       Rank of X matrix continuous variables 
     #
     dimdata <- dim(datadf)
     nnrows <- dimdata[1]
     nncols <- dimdata[2]
     SubsetCode <- rep("_", nnrows)
     for(j in 2:nncols){
          nlevs <- levels(datadf[,j])
          if(!is.null(nlevs)){
               for(i in 1:nnrows){
                    SubsetCode[i] <- paste(SubsetCode[i], datadf[i,j], sep="_") 
               }
          }
     }
     Subsetsdf <- data.frame(datadf[,1], SubsetCode) 

     ###########################################################################################
     # Message regarding removal of observations when it is the only example of a factor level #
     ###########################################################################################
     tableSub <- table(SubsetCode)
     dntableSub <- dimnames(tableSub)$SubsetCode
     ncells <- length(tableSub)
     anyonlyone <- any(tableSub < prank)

     uSubsetCode <- sort(unique(SubsetCode))
     nSC <- length(uSubsetCode)
     Subsetlist <- vector("list", nSC)
     names(Subsetlist) <- uSubsetCode
     for(i in 1:nSC){
          Subsetlist[[i]] <- Subsetsdf[Subsetsdf[,2] == uSubsetCode[i],]
     }
     return(Subsetlist)
}