make the check for k isn't zero after validate qsvPCs is a prcomp object

R/get_qsvs.R

@@ -15,16 +15,17 @@
 #' qsv <- list(x = matrix(seq_len(9), ncol = 3))
 #' get_qsvs(qsv, 2)
 get_qsvs <- function(qsvPCs, k) {
-    # check that k isn't zero
-  if (k <= 0 | k > ncol(qsvPCs$x)) {
-    stop(paste("k must between 1 and",ncol(qsvPCs$x)))
-  }
 
   # Validate qsvPCs is a prcomp object
   if (!is(qsvPCs, "prcomp")) {
     stop("qsvPCs must be a prcomp object.", call. = FALSE)
   }
 
+  # check that k isn't zero
+  if (k <= 0 | k > ncol(qsvPCs$x)) {
+    stop(paste("k must between 1 and",ncol(qsvPCs$x)))
+  }
+
   qSVs <- qsvPCs$x[, seq_len(k), drop = FALSE]
   colnames(qSVs) <- paste0("qSV", seq_len(k))
   return(qSVs)