@@ -63,6 +63,7 @@ TCGAbarcode <- function(barcodes, participant = TRUE, sample = FALSE,

 {

     .checkBarcodes(barcodes)

     filler <- .uniqueDelim(barcodes)

+    stopifnot(is.null(index) || is.numeric(index))

     if (is.null(index))

         index <- which(

             c(rep(participant, 3), sample, portion, plate, center)