R How to Generate Sequences in a Tibble Given Start and End Points

Question

I can't think how to do this in a tidy fashion.

I have a table as follows:

tibble( 
  Min = c(1, 5, 12, 13, 19), 
  Max = c(3, 11, 12, 14, 19), 
  Value = c("a", "bb", "c", "d", "e" ) 
)

and I want to generate another table from it as shown below

tibble(
  Row = c(1:3, 5:11, 12:12, 13:14, 19:19), 
  Value = c( rep("a", 3), rep("bb", 7), "c", "d", "d", "e" ) 
)

Grateful for any suggestions folk might have. The only 'solutions' which come to mind are a bit cumbersome.

Answer 1

1) If DF is the input then:

library(dplyr)

DF %>%
 group_by(Value) %>%
 group_modify(~ tibble(Row = seq(.$Min, .$Max))) %>%
 ungroup

giving:

# A tibble: 14 x 2
   Value   Row
   <chr> <int>
 1 a         1
 2 a         2
 3 a         3
 4 bb        5
 5 bb        6
 6 bb        7
 7 bb        8
 8 bb        9
 9 bb       10
10 bb       11
11 c        12
12 d        13
13 d        14
14 e        19

2) This one creates a list column L containing tibbles and then unnests it. Duplicate Value elements are ok with this one.

library(dplyr)
library(tidyr)

DF %>%
 rowwise %>%
 summarize(L = list(tibble(Value, Row = seq(Min, Max)))) %>%
 ungroup %>%
 unnest(L)