Manipulate/rearrange intervals in R columns

Question

I have a data frame in R with a column (sni) with numbers that looks like this etc

bransch	sni
name	15
name	15
name	16-18
somename	16-18
name	241-3
someothername	241-3

where I have to transform/create a new column with just one number per row, i.e. no intervals so for example it should be a new row for all individual values in the intervals and look like this

bransch	sni
name	15
name	15
name	16
name	17
name	18
somename	16
somename	17
somename	18
name	241
name	242
name	243
someothername	241
someothername	242
someothername	243

I'm a bit unsure which function can do this the best way, or if someone has stumble upon a similar problem/solution. Currently I have tried to split the sni column (where the "-" starts) into two new ones, but then I'm a bit stuck since I will have many rows in one of the new columns without any values etc. Also the column is a character at the moment.

Any advice? Sincerely, TS

Answer 1

I took a while. Here is tidyverse approach:

library(dplyr)
library(tidyr)

df %>% 
  separate(sni, c("x", "y")) %>% 
  as_tibble() %>% 
  mutate(y = ifelse(as.numeric(y)<=9, paste0(substr(x, 1, nchar(x)-1), y),
                                 y)) %>% 
  mutate(id = row_number()) %>% 
  pivot_longer(c(x,y)) %>% 
  mutate(value = as.numeric(value)) %>% 
  group_by(col2 =as.integer(gl(n(),2,n()))) %>% 
  fill(value, .direction = "down") %>% 
  complete(value = seq(first(value), last(value), by=1)) %>% 
  fill(bransch, .direction = "down") %>% 
  select(bransch, sni=value) %>% 
  group_by(col2, sni) %>% 
  slice(1)

   col2 bransch         sni
   <int> <chr>         <dbl>
 1     1 name             15
 2     2 name             15
 3     3 name             16
 4     3 name             17
 5     3 name             18
 6     4 somename         16
 7     4 somename         17
 8     4 somename         18
 9     5 name            241
10     5 name            242
11     5 name            243
12     6 someothername   241
13     6 someothername   242
14     6 someothername   243