# Groups: id [2]
id row val lead_val
<chr> <int> <dbl> <dbl>
1 a 1 1 4
2 a 2 4 9
3 a 3 9 16
4 a 4 16 25
5 a 5 25 36
6 a 6 36 NA
7 b 1 1 8
8 b 2 8 27
9 b 3 27 64
10 b 4 64 125
11 b 5 125 216
12 b 6 216 NA
You can use the dplyr library in R to accomplish this task. The first step would be to create a new dataframe that includes the ID, Year, and RR columns. Next, you can use the lead() function to create a new column that shows the next value of RR. Finally, you can use the filter() function to select only the rows where the Year column is equal to (t+1) and the ID column matches the desired ID. Here is an example code snippet that demonstrates this process:
library(dplyr)
# Create new dataframe with only ID, Year, and RR columns
df_subset <- df %>% select(ID, Year, RR)
# Add a new column showing the next value of RR
df_subset <- df_subset %>% mutate(RR_next = lead(RR))
# Filter dataframe to select rows where Year is (t+1) and ID matches desired value
df_subset_filtered <- df_subset %>% filter(Year == (t+1) & ID == "A.N")
You can then use the filtered dataframe to perform your desired analysis.
thank you so much , but I run the same code which you sent me , i got the below error :
(in_1 <- data.frame(id=rep(letters[1:2],each=6),
+ row=rep(1:6,2),
+ val = c((1:6)^2,(1:6)^3)))
id row val
1 a 1 1
2 a 2 4
3 a 3 9
4 a 4 16
5 a 5 25
6 a 6 36
7 b 1 1
8 b 2 8
9 b 3 27
10 b 4 64
11 b 5 125
12 b 6 216
> group_by(in_1, id) |> mutate(lead_val = lead(val))
Error in `mutate()`:
! Problem while
computing `lead_val =
lead(val)`.
ℹ The error occurred in group
1: id = "a".
Caused by error in `UseMethod()`:
! no applicable method for 'lead' applied to an object of class "c('double', 'numeric')"
Run `rlang::last_error()` to see where the error occurred.
