Operate with a table in R - r

Question

I want to get a tuple from a table in R.
For example, if i have this table named batch_task:
arrival_time, departure_time, jod_id, task_id
11792, 11999, 18, 88
11792, 14331, 18, 82
11792, 12112, 18, 91
16281, 16552, 27, 147
16281, 16396, 27, 139
16281, 16529, 27, 137
So, for each job_id i need a tuple {arrival_time, service_time}; for example, for the job_id = 18, i want to get the tuple {11792, (11999-11792)+(14331-11792)+(12112-11792)} = {11792, 3066}.
Anyone could help me? Thanks in advance,
Jesús

Answer 1

Assuming that batch_task is actually a data frame rather than a table (which is a specific type of R structure dealing with count data), here's a solution using the dplyr package:
library(dplyr)
batch_task %>%
group_by(arrival_time) %>%
summarise(service_time = sum(departure_time - arrival_time), .groups = "drop")
#> # A tibble: 2 x 2
#> arrival_time service_time
#> <int> <int>
#> 1 11792 3066
#> 2 16281 634
Note that there is no data structure called a tuple in R. There are various ways to represent tuples, but the most sensible way in this case would be to keep the result in a data frame format.
Data
batch_task <- structure(list(arrival_time = c(11792L, 11792L, 11792L, 16281L,
16281L, 16281L), departure_time = c(11999L, 14331L, 12112L, 16552L,
16396L, 16529L), jod_id = c(18L, 18L, 18L, 27L, 27L, 27L), task_id = c(88L,
82L, 91L, 147L, 139L, 137L)), class = "data.frame", row.names = c(NA,
-6L))

Answer 2

With the data
batch_task <- structure(list(arrival_time = c(11792L, 11792L, 11792L, 16281L,
16281L, 16281L),
departure_time = c(11999L, 14331L, 12112L, 16552L,
16396L, 16529L),
jod_id = c(18L, 18L, 18L, 27L, 27L, 27L),
task_id = c(88L,
82L, 91L, 147L, 139L, 137L)),
class = "data.frame", row.names = c(NA,
-6L))
I propose this solution
library(tidyverse)
batch_task %>%
mutate(service_time = departure_time - arrival_time) %>%
group_by(jod_id, arrival_time) %>% #assuming arrival_time is equal for each job_id
summarise(service_time = sum(service_time))

Answer 3

Using by.
do.call(rbind, by(d, d$jod_id, function(x) {
a <- x$arrival_time[1]
c(a, sum(x$departure_time - a))
}))
# [,1] [,2]
# 18 11792 3066
# 27 16281 634
Data:
d <- structure(list(arrival_time = c(11792L, 11792L, 11792L, 16281L,
16281L, 16281L), departure_time = c(11999L, 14331L, 12112L, 16552L,
16396L, 16529L), jod_id = c(18L, 18L, 18L, 27L, 27L, 27L), task_id = c(88L,
82L, 91L, 147L, 139L, 137L)), class = "data.frame", row.names = c(NA,
-6L))