Datasets look like this
id start end failure x1
1 0 1 0 0
1 1 3 0 0
1 3 6 1 0
2 0 1 1 1
2 1 3 1 1
2 3 4 0 1
2 4 6 0 1
2 6 7 1 1
As you see, when id = 1, it's just the data input to coxph in survival package. However, when id = 2, at the beginning and end, failure occurs, but in the middle, failure disappears.
Is there a general function to extract data from id = 2 and get the result like id = 1?
I think when id = 2, the result should look like below.
id start end failure x1
1 0 1 0 0
1 1 3 0 0
1 3 6 1 0
2 3 4 0 1
2 4 6 0 1
2 6 7 1 1
A bit hacky, but should get the job done.
Data:
# Load data
library(tidyverse)
df <- read_table("
id start end failure x1
1 0 1 0 0
1 1 3 0 0
1 3 6 1 0
2 0 1 1 1
2 1 3 1 1
2 3 4 0 1
2 4 6 0 1
2 6 7 1 1
")
Data wrangling:
# Check for sub-groups within IDs and remove all but the last one
df <- df %>%
# Group by ID
group_by(
id
) %>%
mutate(
# Check if a new sub-group is starting (after a failure)
new_group = case_when(
# First row is always group 0
row_number() == 1 ~ 0,
# If previous row was a failure, then a new sub-group starts here
lag(failure) == 1 ~ 1,
# Otherwise not
TRUE ~ 0
),
# Assign sub-group number by calculating cumulative sums
group = cumsum(new_group)
) %>%
# Keep only last sub-group for each ID
filter(
group == max(group)
) %>%
ungroup() %>%
# Remove working columns
select(
-new_group, -group
)
Result:
> df
# A tibble: 6 × 5
id start end failure x1
<dbl> <dbl> <dbl> <dbl> <dbl>
1 1 0 1 0 0
2 1 1 3 0 0
3 1 3 6 1 0
4 2 3 4 0 1
5 2 4 6 0 1
6 2 6 7 1 1