Returns the (recursive) parent stations of each specified stop_id.
Recursive in this context means it returns all parents' parents (i.e. first
parents, then parents' parents, and then their parents, and so on).
get_parent_station(gtfs, stop_id = NULL)A GTFS object, as created by read_gtfs().
A string vector including the stop_ids to have their parents
returned. If NULL (the default), the function returns the parents of
every stop_id in the GTFS.
A data.table containing the stop_ids and their parent_stations.
If a stop doesn't have a parent, its correspondent parent_station entry
is marked as "".
data_path <- system.file("extdata/ggl_gtfs.zip", package = "gtfstools")
gtfs <- read_gtfs(data_path)
parents <- get_parent_station(gtfs)
head(parents)
#> stop_id parent_station
#> <char> <char>
#> 1: F12
#> 2: E1 F12
#> 3: E2 F12
#> 4: E3 F12
#> 5: E4 F12
#> 6: E5 F12
# use the stop_id argument to control which stops are analyzed
parents <- get_parent_station(gtfs, c("B1", "B2"))
parents
#> stop_id parent_station
#> <char> <char>
#> 1: B1 F12S
#> 2: B2 F12N
#> 3: F12S F12
#> 4: F12N F12
#> 5: F12