Convert a data set to 0-1 format for binary diagnostic outcomes

binary.recode <- function(dat, pos.label = "Positive")
{
    ## Purpose: Convert a data set to 0-1 format for binary diagnostic outcomes
    ## Arguments:
    ##   dat: a data frame with binary diagnostic outcomes
    ##   pos.label: a label for the positive outcome that is used in the "dat"
    ## Return: a data frame with binary diagnostic outcomes that are coded as numeric 0 or 1. 
    ## Author: Feiming Chen
    ## ________________________________________________

    dat[] <- lapply(dat, function(x, p=pos.label) ifelse(x == p, 1, 0))
    dat
}
if (F) {                                # Unit Test
    binary.recode(data.frame(x = rep("Positive", 2), y = rep("Negative", 2)))
    ##   x y
    ## 1 1 0
    ## 2 1 0
}