How to duplicate column rows and fill an added column with one item in list-CodePudding

I have a dataframe with the following columns:

tester <- data.frame(id = c(123456789, 987654321))
tester$furniture <- list(c("chair"), c("bed", "bench", "barstool"))
tester$count <- c(1,3)

Based on the value in the count column, each row is repeated [count] number of times:

tester[rep(seq_len(dim(tester_2)[1]), tester$count), ]

The number of items in the furniture list will always be equal to the count value

I want to create a new column that contains one item from the list, in order from the first through the last list item. I would manually input what I want in this new column as:

tester$new <- c("chair", "bench", "bed", "barstool")

but this doesn't work now because the dataframe resulting from the above code only technically has two rows.

Any advice would be greatly appreciated!

CodePudding user response：

You could achieve it with unnest() from tidyr:

tidyr::unnest(tester, furniture)

# # A tibble: 4 × 3
#          id furniture count
#       <dbl> <chr>     <dbl>
# 1 123456789 chair         1
# 2 987654321 bed           3
# 3 987654321 bench         3
# 4 987654321 barstool      3

If you want to preserve the list-column, then

library(tidyverse)

tester %>%
  mutate(new = furniture) %>%
  unnest(new)

# # A tibble: 4 × 4
#          id furniture count new     
#       <dbl> <list>    <dbl> <chr>   
# 1 123456789 <chr [1]>     1 chair   
# 2 987654321 <chr [3]>     3 bed     
# 3 987654321 <chr [3]>     3 bench   
# 4 987654321 <chr [3]>     3 barstool

CodePudding user response：

You could also use the function unchop from tidyr like this:

tester <- data.frame(id = c(123456789, 987654321)) 
tester$furniture <-  list(c("chair"), c("bed", "bench", "barstool")) 
tester$count <- c(1,3)

library(tidyr)
unchop(tester, id:count)
#>          id furniture count
#> 1 123456789     chair     1
#> 2 987654321       bed     3
#> 3 987654321     bench     3
#> 4 987654321  barstool     3

^{Created on 2022-07-14 by the reprex package (v2.0.1)}

And if you want to keep the furniture column you can use this:

tester <- data.frame(id = c(123456789, 987654321)) 
tester$furniture <-  list(c("chair"), c("bed", "bench", "barstool")) 
tester$count <- c(1,3)

library(dplyr)
library(tidyr)
tester %>% 
  mutate(new = furniture) %>%
  unchop(new)
#>          id            furniture count      new
#> 1 123456789                chair     1    chair
#> 2 987654321 bed, bench, barstool     3      bed
#> 3 987654321 bed, bench, barstool     3    bench
#> 4 987654321 bed, bench, barstool     3 barstool

^{Created on 2022-07-14 by the reprex package (v2.0.1)}