I can split character separated values in a cell into rows with tidyr::separate_longer_delim. However, is there a simpley way to add a column with an index?
I have (example from https://tidyr.tidyverse.org/reference/separate_longer_delim.html)
library(tidyr)
df <- tibble(id = 1:4, x = c("x", "x y", "x y z", NA))
df %>% separate_longer_delim(x, delim = " ")
#> # A tibble: 7 × 2
#> id x
#> <int> <chr>
#> 1 1 x
#> 2 2 x
#> 3 2 y
#> 4 3 x
#> 5 3 y
#> 6 3 z
#> 7 4 NA
And I want
#> # A tibble: 7 × 2
#> id x index
#> <int> <chr> <int>
#> 1 1 x 1
#> 2 2 x 1
#> 3 2 y 2
#> 4 3 x 1
#> 5 3 y 2
#> 6 3 z 3
#> 7 4 NA 1
Try mutate + row_number() by the group id
library(tidyverse)
tibble(id = 1:4, x = c("x", "x y", "x y z", NA)) %>%
separate_longer_delim(x, delim = " ") %>%
mutate(index = row_number(), .by = id)
# A tibble: 7 × 3
id x index
<int> <chr> <int>
1 1 x 1
2 2 x 1
3 2 y 2
4 3 x 1
5 3 y 2
6 3 z 3
7 4 NA 1