is_sample_stats: Test if elements in sample column are statistics
Description
In stochastic simulations, PLEXOS will return sample results and their statistics together. This function
makes it easy to separate them with a filter.
db <- plexos_open()
res <- query_month(db, "Generator", "Generation")
res %>% filter(sample_stats(sample)) # To obtain statisticsres %>% filter(!sample_stats(sample)) # To obtain sample results