splitting text in column and add row number [duplicate]

Answer 1

I'm biased in favor of cSplit from the "splitstackshape" package, but you might be interested in unnest from "tidyr" in conjunction with "dplyr":

library(dplyr)
library(tidyr)
df %>%
  mutate(b = strsplit(b, ";")) %>%
  unnest(b)
#   a b
# 1 1 g
# 2 1 j
# 3 1 n
# 4 2 x
# 5 2 f
# 6 2 v