export_data: Extract results from the kmeans analysis
In pegoraro/qchlorophyll: qchlorophyll

This function is used to extract the best results from the kmeans analysis. The best result is considered to be the result characterized by the highest Calinski-Harabasz index.

export_data(x, nc_dataframe, final_kmeans_results, filename,
  export_vars = list("lon", "lat", "id_pixel", "gruppo"),
  join_by = c("id_pixel", "lon", "lat"), unique_id = list("lon", "lat",
  "id_pixel"))

`x`	dataframe used in the kmeans analysis (prior to standardization)
`nc_dataframe`	main dataframe
`final_kmeans_results`	list of the final results obtained from the function extract_results
`filename`	name of the .csv file to export
`export_vars`	variables to export. A list of characters
`join_by`	variables to join by. A vector of characters
`unique_id`	a list of unique identifiers