R/duplicates_in_column.R

In vvauditor: Creates Assertion Tests

#' Duplicates in column
#'
#' Searches for duplicates in a data frame column.
#'
#' @param df Data frame.
#' @param col Column name.
#' @return Rows containing duplicated values.
#' @family tests
#' @examples
#' duplicates_in_column(mtcars, "mpg")
#'
#' @export
duplicates_in_column <- function(df, col) {
  ## Check if object "df" is a data frame.
  if (!is.data.frame(df)) {
    return(warning("df is not a data frame"))
  }
  ## Check if column exists in df.
  if (!col %in% names(df)) {
    return(warning("The specified column does not exist in the data frame."))
  }


  values_col <- df[[col]]

  duplicates <- unique(values_col[duplicated(values_col)])

  duplicates_df <- df[values_col %in% duplicates, ]

  return(duplicates_df)
}