old_source/R/subset_repos.R

In kamapu/gisrepos: Repositories of Spatial Data Sets for Environmental Sciences

#' @name subset_repos
#' 
#' @title Produce a subset of repository list
#' 
#' @description 
#' Produces a subset considering all relationships between data frames included
#' in a list structured as in [.gisrepos].
#' 
#' @param db A list structured in the same way as [.gisrepos].
#' @param idx A vector indicating the rows to be selected in the data frame
#'     `data_sets` within 'db'. It may be either an integer, a logical or a
#'     character vector. In the later case, rows in `data_sets` have to be
#'     named.
#' 
#' @return A list including the subset of 'db'.
#' 
#' @examples 
## #' first_repos <- subset_db(.gisrepos, 1:5)
#' 
#' @export subset_db
#' 
subset_db <- function(db, idx) {
	db <- with(db, {
				data_sets <- data_sets[idx,]
				fk_links <- fk_links[fk_links$id %in% data_sets$id,]
				fk_keywords <- fk_keywords[fk_keywords$id %in% data_sets$id,]
				links <- links[links$link_id %in% fk_links$link_id,]
				keywords <- keywords[keywords$kword_id %in% fk_keywords$kword_id,]
				list(data_sets=data_sets, links=links, keywords=keywords,
						fk_links=fk_links, fk_keywords=fk_keywords)
			})
	return(db)
}