Как насчет этого?
df %>%
mutate_at(vars(ends_with("Date")), function(x) as.Date(x, format = "%m/%d/%Y")) %>%
group_by(ID, Medication) %>%
mutate(
isConsecutive = lead(Start.Date) - Stop.Date == 1,
isConsecutive = ifelse(
is.na(isConsecutive) & lag(isConsecutive) == TRUE, FALSE, isConsecutive),
grp = cumsum(isConsecutive)) %>%
group_by(ID, Medication, grp) %>%
mutate(Start.Date = min(Start.Date), Stop.Date = max(Stop.Date)) %>%
slice(1) %>%
ungroup() %>%
select(-isConsecutive, -grp)
## A tibble: 5 x 4
# ID Medication Start.Date Stop.Date
# <dbl> <fct> <date> <date>
#1 2. aspirin 2017-05-01 2017-05-10
#2 2. aspirin 2017-06-20 2017-06-27
#3 2. tylenol 2017-05-01 2017-05-15
#4 3. lipitor 2017-05-06 2017-05-12
#5 5. advil 2017-05-28 2017-06-13
Лучше всего проверить это на нескольких примерах, чтобы убедиться в надежности. Давайте попробуем более сложный пример
df <- structure(list(ID = c(2, 2, 2, 2, 2, 3, 5, 5), Medication = structure(c(2L,
2L, 2L, 2L, 4L, 3L, 1L, 1L), .Label = c("advil", "aspirin", "lipitor",
"tylenol"), class = "factor"), Start.Date = structure(c(1L, 2L,
6L, 7L, 1L, 3L, 4L, 5L), .Label = c("05/01/2017", "05/05/2017",
"05/06/2017", "05/28/2017", "06/14/2017", "06/20/2017", "06/28/2017"
), class = "factor"), Stop.Date = structure(c(2L, 3L, 8L, 1L,
5L, 4L, 6L, 7L), .Label = c("04/30/2017", "05/04/2017", "05/10/2017",
"05/12/2017", "05/15/2017", "06/13/2017", "06/20/2017", "06/27/2017"
), class = "factor")), .Names = c("ID", "Medication", "Start.Date",
"Stop.Date"), row.names = c(NA, -8L), class = "data.frame")
df;
# ID Medication Start.Date Stop.Date
#1 2 aspirin 05/01/2017 05/04/2017
#2 2 aspirin 05/05/2017 05/10/2017
#3 2 aspirin 06/20/2017 06/27/2017
#4 2 aspirin 06/28/2017 04/30/2017
#5 2 tylenol 05/01/2017 05/15/2017
#6 3 lipitor 05/06/2017 05/12/2017
#7 5 advil 05/28/2017 06/13/2017
#8 5 advil 06/14/2017 06/20/2017
Обратите внимание, что здесь у нас есть два последовательных блока для ID=2
(строки 1 + 2 и строки 3 + 4), а также один последовательный блок для ID=5
(строки 7 + 8).
Выход
df %>%
mutate_at(vars(ends_with("Date")), function(x) as.Date(x, format = "%m/%d/%Y")) %>%
group_by(ID, Medication) %>%
mutate(
isConsecutive = lead(Start.Date) - Stop.Date == 1,
isConsecutive = ifelse(
is.na(isConsecutive) & lag(isConsecutive) == TRUE, FALSE, isConsecutive),
grp = cumsum(isConsecutive)) %>%
group_by(ID, Medication, grp) %>%
mutate(Start.Date = min(Start.Date), Stop.Date = max(Stop.Date)) %>%
slice(1) %>%
ungroup() %>%
select(-isConsecutive, -grp)
## A tibble: 5 x 4
# ID Medication Start.Date Stop.Date
# <dbl> <fct> <date> <date>
#1 2. aspirin 2017-05-01 2017-05-10
#2 2. aspirin 2017-06-20 2017-06-27
#3 2. tylenol 2017-05-01 2017-05-15
#4 3. lipitor 2017-05-06 2017-05-12
#5 5. advil 2017-05-28 2017-06-20
Результаты кажутся достоверными.