Draft data_expand()

NAMESPACE

@@ -228,6 +228,7 @@ export(data_adjust)
 export(data_arrange)
 export(data_codebook)
 export(data_duplicated)
+export(data_expand)
 export(data_extract)
 export(data_filter)
 export(data_find)

R/data_expand.R

@@ -0,0 +1,69 @@
+#' @title Expand (i.e. replicate rows) a data frame
+#' @name data_expand
+#'
+#' @description
+#' Expand a data frame by replicating rows based on another variable that
+#' contains the counts of replications per row.
+#'
+#' @param data A data frame.
+#' @param expand The name of the column that contains the counts of replications
+#' for each row.
+#' @param ... Currently not used.
+#' @inheritParams find_columns
+#'
+#' @return `data`, with each row replicated as many times as defined in `expand`.
+#'
+#' @examples
+#' data(mtcars)
+#' data_expand(head(mtcars), "carb")
+#' @export
+data_expand <- function(data,
+                        expand = NULL,
+                        select = NULL,
+                        exclude = NULL,
+                        remove_na = FALSE,
+                        ignore_case = FALSE,
+                        verbose = TRUE,
+                        regex = FALSE,
+                        ...) {
+  # we need a name for the new column
+  if (is.null(expand)) {
+    insight::format_error(
+      "No column that should be used to expand the data frame was provided. Please use `expand` to define a column."
+    )
+  }
+
+  # only one column name
+  if (length(expand) > 1) {
+    insight::format_error(
+      "Please provide only a single string for `expand`, no character vector with multiple values."
+    )
+  }
+
+  # check if in data
+  if (!expand %in% colnames(data)) {
+    insight::format_error(
+      "The column provided in `expand` does not exist in the data frame.",
+      .misspelled_string(colnames(data), expand, "Possibly misspelled?")
+    )
+  }
+
+  # evaluate select/exclude, may be select-helpers
+  select <- .select_nse(select,
+    data,
+    exclude,
+    ignore_case,
+    regex = regex,
+    verbose = verbose
+  )
+
+  # extract variable that contains the counts of replicates
+  replicates <- data[[expand]]
+  # we can remove that column now
+  data[[replicates]] <- NULL
+
+  # fin
+  as.data.frame(do.call(cbind, lapply(data[select], function(variable) {
+    unlist(Map(rep, variable, replicates), use.names = FALSE)
+  })))
+}

_pkgdown.yaml

@@ -20,6 +20,7 @@ reference:
       - data_partition
       - data_rotate
       - data_group
+      - data_expand
       - data_duplicated
       - data_unique