Helper Functions for Sub-Set Operations on Recursive Objects

'squarebrackets' provides some helper functions for sub-set operations on recursive objects (lists and data.frames).

dropl(x) returns x[[1L]] if length(x) == 1, and returns x otherwise.
This can be used for the *_x and *_wo methods on recursive objects, where one would like to extract the contents of the singular selection.

Usage

dropl(x)

Arguments

x

a list.

Value

For dropl():
If length(x) == 1L, dropl(x) returns x[[1L]];
otherwise it returns the original x unchanged.

Examples

obj <- as.list(1:10)
ii_x(obj, 1) |> dropl() # equivalent to obj[[1L]]
#> [1] 1