#2247 - Update derive_vars_transposed() with relationship argument.

R/derive_vars_transposed.R

@@ -24,6 +24,16 @@
 #'
 #' @param filter Expression used to restrict the records of `dataset_merge` prior to transposing
 #'
+#' @param relationship Expected merge-relationship between the `by_vars`
+#'   variable(s) in `dataset` and `dataset_merge` (after transposition)
+#'
+#'   This argument is passed to the `dplyr::left_join()` function. See
+#'   https://dplyr.tidyverse.org/reference/mutate-joins.html#arguments for
+#'   more details.
+#'
+#'   Permitted Values for `relationship`: `"one-to-one"`, `"one-to-many"`,
+#'   `"many-to-one"`, `"many-to-many"`, `NULL`.
+#'
 #' @details
 #' After filtering `dataset_merge` based upon the condition provided in `filter`, this
 #' dataset is transposed and subsequently merged onto `dataset` using `by_vars` as
@@ -84,19 +94,25 @@ derive_vars_transposed <- function(dataset,
                                    by_vars,
                                    key_var,
                                    value_var,
-                                   filter = NULL) {
+                                   filter = NULL,
+                                   relationship = NULL) {
   key_var <- assert_symbol(enexpr(key_var))
   value_var <- assert_symbol(enexpr(value_var))
   filter <- assert_filter_cond(enexpr(filter), optional = TRUE)
   assert_vars(by_vars)
   assert_data_frame(dataset, required_vars = replace_values_by_names(by_vars))
   assert_data_frame(dataset_merge, required_vars = expr_c(by_vars, key_var, value_var))
+  relationship <- assert_character_scalar(
+    relationship,
+    values = c("one-to-one", "one-to-many", "many-to-one", "many-to-many"),
+    case_sensitive = TRUE,
+    optional = TRUE)
 
   dataset_transposed <- dataset_merge %>%
     filter_if(filter) %>%
     pivot_wider(names_from = !!key_var, values_from = !!value_var)
 
-  left_join(dataset, dataset_transposed, by = vars2chr(by_vars))
+  left_join(dataset, dataset_transposed, by = vars2chr(by_vars), relationship = relationship)
 }
 
 #' Derive ATC Class Variables