filter_by_weekday {gtfstools}

Filter GTFS object by weekday

Description

Filters a GTFS object by weekday, keeping (or dropping) the relevant entries in each file.

Usage

filter_by_weekday(gtfs, weekday, combine = "or", keep = TRUE)

Arguments

gtfs

A GTFS object, as created by read_gtfs().

weekday

A character vector. The weekdays used to filter the data. Possible values are c("monday", "tuesday", "wednesday", "thursday", "friday", "saturday", "sunday").

combine

A string. Specifies which logic operation (OR or AND) should be used to filter the calendar table when multiple weekdays are specified. Defaults to "or". Please check the details and examples sections for more information on this argument usage.

keep

A logical. Whether the entries related to the specified weekdays should be kept or dropped (defaults to TRUE, which keeps the entries).

Value

The GTFS object passed to the gtfs parameter, after the filtering process.

combine usage

When filtering the calendar table using weekdays, one could reason about the process in different ways. For example, you may want to keep only services who run on mondays AND tuesdays. Or you may want to keep services that run EITHER on mondays OR on tuesdays. The first case is the equivalent of filtering using the expression monday == 1 & tuesday == 1, while the second uses monday == 1 | tuesday == 1. You can use the combine argument to control this behaviour.

Please note that combine also works together with keep. Using the same examples listed above, you could either keep the entries related to services that run on mondays and tuesdays or drop them, depending on the value you pass to keep.

See Also

Other filtering functions: filter_by_agency_id(), filter_by_route_id(), filter_by_route_type(), filter_by_service_id(), filter_by_sf(), filter_by_shape_id(), filter_by_stop_id(), filter_by_time_of_day(), filter_by_trip_id()

Examples

# read gtfs
data_path <- system.file("extdata/spo_gtfs.zip", package = "gtfstools")
gtfs <- read_gtfs(data_path)

object.size(gtfs)

# keeps entries related to services than run EITHER on monday OR on sunday
smaller_gtfs <- filter_by_weekday(gtfs, weekday = c("monday", "sunday"))
smaller_gtfs$calendar[, c("service_id", "monday", "sunday")]
object.size(smaller_gtfs)

# keeps entries related to services than run on monday AND on sunday
smaller_gtfs <- filter_by_weekday(
  gtfs,
  weekday = c("monday", "sunday"),
  combine = "and"
)
smaller_gtfs$calendar[, c("service_id", "monday", "sunday")]
object.size(smaller_gtfs)

# drops entries related to services than run EITHER on monday OR on sunday
# the resulting gtfs shouldn't include any trips running on these days
smaller_gtfs <- filter_by_weekday(
  gtfs,
  weekday = c("monday", "sunday"),
  keep = FALSE
)
smaller_gtfs$calendar[, c("service_id", "monday", "sunday")]
object.size(smaller_gtfs)

# drops entries related to services than run on monday AND on sunday
# the resulting gtfs may include trips that run on these days, but no trips
# that run on both these days
smaller_gtfs <- filter_by_weekday(
  gtfs,
  weekday = c("monday", "sunday"),
  combine = "and",
  keep = FALSE
)
smaller_gtfs$calendar[, c("service_id", "monday", "sunday")]
object.size(smaller_gtfs)