Reduce loops using purrr base R pipe. Inspired by https://masalmon.eu/2023/07/26/reduce/

reduce-loop-using-pipes.R

library(purrr)

# The intial information
elements <- tibble::tribble(
  ~key          , ~values   ,
  "Barbie"      , "shoes"   ,
  "Oppenheimer" , "history"
)

# Aditional values we want to proces
additional_values <- list(
  list(key = "Barbie", values = "sparkles"),
  list(key = "Barbie", values = "feminism"),
  list(key = "Oppenheimer", values = "fire")
)

# Function to process each value to a single value
reduce_values <- \(value, next_value) {
  value[value[["key"]] == next_value[["key"]], ][["values"]] <-
    toString(c(
      value[value[["key"]] == next_value[["key"]], ][["values"]],
      value[["values"]]
    ))
  value
}

# Adding the aditional values to the elements table
elements |>
  purrr::reduce(.x = additional_values, .f = reduce_values, .init = _)