R/combinations.R

In jchitpin/blistR:

combinations <- function(chooseK, nameFeature){

    if(round(chooseK) != chooseK || chooseK <= 0){
        stop("chooseK must be a positive integer.")
    }

    ## Initialize output
    combinations <- vector("list", length=chooseK)

    ## Populate combinations of each N choose K
    for(i in 1:chooseK){
        combinations[[i]] <- t(combn(chooseK, i, function(x) {z=integer(chooseK);z[x]=1;z}))
    }
    combinations <- do.call(rbind, combinations)
    colnames(combinations) <- nameFeature

    return(combinations)
}