I'm struggling to solve a seemingly simple task. In this type of data:
df <- data.frame(
A = c(1,2,3,4,1,2,3,2,2,2,2,1,1,1,1,6,7)
)
I want to add an id variable that groups column A by a regular interval, say, of 5. An additional difficulty is that the number of rows is 17, thus not a multiple of 5:
df <- data.frame(
A = c(1,2,3,4,1,2,3,2,2,2,2,1,1,1,1,6,7),
id = c("a","a","a","a","a",
"b","b","b","b","b",
"c","c","c","c","c",
"d","d"))
How can this be done?
A possible solution:
library(dplyr)
df <- data.frame(
A = c(1,2,3,4,1,2,3,2,2,2,2,1,1,1,1,6,7)
)
df %>%
mutate(id = rep(letters, each=5)[1:n()])
#> A id
#> 1 1 a
#> 2 2 a
#> 3 3 a
#> 4 4 a
#> 5 1 a
#> 6 2 b
#> 7 3 b
#> 8 2 b
#> 9 2 b
#> 10 2 b
#> 11 2 c
#> 12 1 c
#> 13 1 c
#> 14 1 c
#> 15 1 c
#> 16 6 d
#> 17 7 d