Rescaling many variables at once

Use the following function to rescale variables:

rescale.many <- function(dat, column.nos) { 
  nms <- names(dat) 
  for(col in column.nos) { 
    name <- paste(nms[col],".rescaled", sep = "") 
    dat[name] <- rescale(dat[,col]) 
  } 
  cat(paste("Rescaled ", length(column.nos),      " variable(s)n")) 
  dat 
} 

With the preceding function defined, we can do the following to rescale the first and fourth variables in the data frame:

> rescale.many(students, c(1,4))