Take unique() of add_vars, x, and y

NEWS.md

@@ -10,6 +10,7 @@
 - `print.shapviz()` now shows top two rows of SHAP matrix.
 - Re-activate all unit tests.
 - Added "How to contribute" to README.
+- `sv_dependence2D()`: In case `add_vars` are passed, `x` and/or `y` are removed from it in order to not use any variable twice.
 
 # shapviz 0.9.2
 

R/sv_dependence2D.R

@@ -7,7 +7,8 @@
 #' maybe other regional features that can be passed via `add_vars`).
 #'
 #' If SHAP interaction values are available, setting `interactions = TRUE` allows
-#' to focus on pure interaction effects (multiplied by two).
+#' to focus on pure interaction effects (multiplied by two). In this case, `add_vars`
+#' has no effect.
 #'
 #' @importFrom rlang .data
 #'
@@ -114,7 +115,7 @@ sv_dependence2D.shapviz <- function(object, x, y,
 
   # Color variable
   if (!interactions) {
-    s <- rowSums(S[, c(x, y, add_vars)])
+    s <- rowSums(S[, unique(c(x, y, add_vars))])  # unique() if add_vars contains x or y
   } else {
     s <- S_inter[, x, y]
     if (x != y) {