dplyr - Linking Flights in a Schedule with R

Question

I have a tibble of flights for a given airline schedule that I am trying to 'link' together. The data follows the IATA SSIM format, or more explicitly contains the current flight 'key' and the following flight 'key'. I am trying to 'link' these flights to determine the number of aircraft in that schedule. For example, if a schedule looks like:

flight123 -> flight456 -> flight789 -> end
flight987 -> flight654 -> flight321 -> end

This would require two (2) aircraft to fly. I have been able to accomplish this using which(), match(), or filter(), but I am having issues with the speed. My tibble has over 200,000 rows so this is taking more than 8 minutes to return. I would like this to return in less than a minute, if possible. Example below:

library(tidyverse)
dat %>% mutate(nextIndex = purrr::map(nextKey, function(id){match(x = id, table = dat$key)}))

Could group_by() or nest() help to improve speed? Using a for() loop took an absurd amount of time...

Here is a slice of the data... unfortunately, the IATA industry standard format does not include much data as the format is ancient. The key is defined as {FlightNumber}/{DepartureDate}{Origin}. Tail numbers are not assigned and therefore not available.

# A tibble: 10 x 2
   key             nextKey        
   <glue>          <glue>         
 1 3845/13Apr19GGG 3876/13Apr19DFW
 2 246/29Apr19CLT  123/29Apr19PBI  
 3 2561/24Apr19PHX 2604/24Apr19BOS
 4 2101/01Apr19DCA 1660/01Apr19DFW
 5 3443/21Apr19BTR 3703/21Apr19DFW
 6 2772/07Apr19JFK 1810/07Apr19AUS
 7 784/21Apr19BWI  NA 
 8 5199/25Apr19PHL 5090/25Apr19HVN
 9 375/14Apr19JAX  2360/14Apr19DFW
10 5517/30Apr19YYZ 5301/30Apr19DCA

Ideally, I would like the final result to be grouped or nested by each individual line of flying (aircraft).

question from:https://stackoverflow.com/questions/65832426/linking-flights-in-a-schedule-with-r

Answer 1

Waitting for answers