- r nested-lists names
- Updated Sat, 16 Jul 2022 14:33:28 GMT

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))
```