a5_cell_to_children(), a5_grid_disk() and a5_spherical_cap() return
an a5_cell_list when called with simplify = FALSE: a
vctrs::list_of() holding one a5_cell vector per input, usable as a
list column. It behaves as any list: lengths() gives the number of cells
per input, [[ extracts one element, and tidyr::unnest() expands it to
one row per cell.
Usage
as_a5_cell_list(x)
# S3 method for class 'a5_cell_list'
unlist(x, recursive = TRUE, use.names = TRUE)Arguments
- x
An
a5_cell_list, or foras_a5_cell_list()a list of a5_cell vectors.- recursive, use.names
Ignored.
Details
unlist() concatenates the elements into a single a5_cell vector,
equivalent to vctrs::list_unchop(). Without this method base
unlist() would descend into the raw byte fields of the record and return
a meaningless raw vector. The recursive and use.names arguments are
accepted for compatibility and ignored.
as_a5_cell_list() wraps a plain list of a5_cell vectors (for example
the output of lapply()) so that unlist() works on it. Elements that
are hex strings are converted; NULL elements become empty.
Examples
cells <- a5_lonlat_to_cell(c(-3.19, 0), c(55.95, 0), resolution = 5)
lst <- a5_cell_to_children(cells, simplify = FALSE)
lengths(lst)
#> [1] 4 4
unlist(lst)
#> <a5_cell[8]>
#> [1] 6314800000000000 6315800000000000 6316800000000000 6317800000000000
#> [5] 4f08800000000000 4f09800000000000 4f0a800000000000 4f0b800000000000
# lapply() produces a plain list, on which base unlist() would return raw
# bytes; wrap it first.
plain <- lapply(seq_along(cells), function(i) a5_cell_to_children(cells[i]))
unlist(as_a5_cell_list(plain))
#> <a5_cell[8]>
#> [1] 6314800000000000 6315800000000000 6316800000000000 6317800000000000
#> [5] 4f08800000000000 4f09800000000000 4f0a800000000000 4f0b800000000000