R/Utils.R

In dsld: Data Science Looks at Discrimination

# many functions in dsld are wrappers for functions in other packages;
# in order to avoid "package bloat," we instead check for them as needed

# e.g. say a dsld function f() wraps some function in package p; then
# instead of listing p as imported etc. in the dsld DESCRIPTION file, 
# we write the top of f(), getSuggestedLib('p'); this loads p if it is
# installed on the user's machine, otherwise so informs the user

getSuggestedLib <- function(pkgName) {
   if (!requireNamespace(pkgName,quietly=TRUE))
      stop(paste0(pkgName, ' not loaded'))
}

pr2file <- function(filename)
{
   origdev <- dev.cur()
   parts <- strsplit(filename,".",fixed=TRUE)
   nparts <- length(parts[[1]])
   suff <- parts[[1]][nparts]
   if (suff == "pdf") {
       pdf(filename)
   }
   else if (suff == "png") {
       png(filename,bg='white')
   }
   else jpeg(filename)
   devnum <- dev.cur()
   dev.set(origdev)
   dev.copy(which = devnum)
   dev.set(devnum)
   dev.off()
   dev.set(origdev)
}

# generates a "cartesian product" of factor levels from input factors

cartFactorLvls <- function(factorNames) 
{
   theLevels <- lapply(factorNames,function(fName) levels(get(fName)))
   expand.grid(theLevels)
}

### --------------------------- dsldGetRow5 ------------------------------------
### selects 5 rows for comparison across each level of the sensitive variable
### randomly if the user doesn't supply data in the interactions case
### USEFUL FOR: dsldLinear, dsldLogit
dsldGetRow5 <- function(data, yName, sName) {
  rows <- sample(nrow(data), 5)
  reducedData <- data[rows, ]
  columns <- c(yName, sName)
  newDat <- reducedData[, !(names(reducedData) %in% columns)]
  result <- sprintf("No user sComparisonPts supplied. The following rows 
                    are selected: %s,%s,%s,%s,%s", rows[1],rows[2],rows[3],rows[4],
                    rows[5]); print(result)
  return(newDat)
}