How to select elements with the same name from nested list with purrr?

Question

require(purrr)

list <- list( 
  node = list(a = list(y = 1, t = 1), b = list(y = 1, t = 2)),
  node = list(a = list(y = 1, t = 3), b = list(y = 1, t = 4))) 
<         


        

Answer 1

Here are some ideas using functions from purrr. Thanks for the great suggestions from @cderv.

Here is the first one. The use of pluck is similar to $.

list %>% flatten() %>% transpose() %>% pluck("t")
$a
[1] 1

$b
[1] 2

$a
[1] 3

$b
[1] 4

Here is the second one.

list %>% flatten() %>% map("t") 
$a
[1] 1

$b
[1] 2

$a
[1] 3

$b
[1] 4

Finally, if we want a vector, we can use map_dbl if we know the elements in t are all numeric.

list %>% flatten() %>% map_dbl("t")
a b a b 
1 2 3 4