Applying Between function to a list column

Question

I'm working with a data frame where each row contains 3 columns: a left bound, right bound and a list of values "pool".

    test <- structure(list(left = c(645, 1292, 220, 450), right = c(669, 
1309, 230, 600), pool = list(structure(c(1242L, 1469L), match.length = c(6L, 
6L), index.type = "chars", useBytes = TRUE), structure(c(223L, 
833L, 987L, 1513L, 1759L, 1805L, 2244L), match.length = c(6L, 
6L, 6L, 6L, 6L, 6L, 6L), index.type = "chars", useBytes = TRUE), 
    structure(223L, match.length = 6L, index.type = "chars", useBytes = TRUE), 
    structure(c(248L, 491L, 568L, 811L, 1151L, 1200L), match.length = c(6L, 
    6L, 6L, 6L, 6L, 6L), index.type = "chars", useBytes = TRUE))), row.names = c(NA, 
-4L), class = c("tbl_df", "tbl", "data.frame"))

What I'm trying to accomplish is

for each row, are any of the values in the pool between the left and right bounds? This should return a vector of FALSE FALSE TRUE TRUE
which element(s) of the list are between the bounds? Should return NA NA 223 (491,568)

I'm getting close using lapply and specifying the index of each row individually.

> lapply(test$pool[1], between, left = test$left[1], right = test$right[1])
[[1]]
[1] FALSE FALSE

> lapply(test$pool[2], between, left = test$left[2], right = test$right[2])
[[1]]
[1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE

> lapply(test$pool[3], between, left = test$left[3], right = test$right[3])
[[1]]
[1] TRUE

> lapply(test$pool[4], between, left = test$left[4], right = test$right[4])
[[1]]
[1] FALSE  TRUE  TRUE FALSE FALSE FALSE

But I'm not good enough with lists yet to get my head around how to apply this over all the rows of the dataframe for part 1, or to extract out the list entries for part 2.

Thanks for your expertise!

langtang · Answer

You can use create a small function that checks if there are values between left and right, and returns those values (if any), and apply that function rowwise:

f <- function(l,r,p) {
  bvals = between(p,l,r)
  list(hasvals=any(bvals),vals=p[bvals])
}

test %>% 
  rowwise %>% 
  mutate(r = list(f(left,right, pool))) %>% 
  unnest_wider(r)

Output:

   left right pool      hasvals vals     
              
1   645   669  FALSE      
2  1292  1309  FALSE      
3   220   230  TRUE    
4   450   600  TRUE

GuedesBF · Answer

We can use rowwise, create a temporary column with a logical index for every element of pool values, use this index to create the logical between_any and integer values columns, then finally remove the index column.

library(dplyr)

test %>% rowwise() %>% 
    mutate(between = list(between(pool, left, right)),
           between_any = any(between),
           values = list(pool[between])) %>% 
    select(-between) %>% 
    ungroup()

# A tibble: 4 × 5
   left right pool      between_any values   
                  
1   645   669  FALSE       
2  1292  1309  FALSE       
3   220   230  TRUE        
4   450   600  TRUE

Applying Between function to a list column

2 Answers