I have a nested list. Each level of this list is named (as in provided dummy example). I want to extract the names (unique) from the 2nd level of my initial list, so I will be able to use them in some further operations.
I know how to do it in two steps, but I wonder whether there is more efficient/elegant solution. Also I wonder whether the regex approach would be faster (I am noob at regex).
Here is a dummy list:
x <- list(one = list(one_1 = list(seq = 1:9, start = 1, end = 5),
one_2 = list(seq = 2:11, start = 2, end = 6),
one_3 = list(seq = 3:12, start = 3, end = 7)),
two = list(two_1 = list(seq = 1:13, start = 8, end = 222),
two_2 = list(seq = 1:14, start = 13, end = 54)))
And here is my code:
allnames <- names(rapply(x, function(x) head(x, 1)))
desirednames <- unique(sapply(strsplit(allnames, ".", fixed=TRUE), "[", 2))
A possible solution, based on purrr::map_depth:
library(tidyverse)
map_depth(x, 1, names) %>% unlist(use.names = F)
#> [1] "one_1" "one_2" "one_3" "two_1" "two_2"