Register / look up a direct crosswalk — register_scale

A registered map short-circuits the atom-layer derivation in scale_map() or scale_map_between() (and thereby recast_scale()) for one pair of resolutions – for cases where the exact correspondence is known (hand-audited crosswalks, official concordance tables).

register_scale_map(x, from, to, map)

register_scale_map_between(from, to, map)

get_scale_map(x, from, to)

get_scale_map_between(from, to)

list_scale_maps()

Arguments

x: The NestedScale the frames belong to, or its name.
from, to: For the within-scale functions, frame names of x. For the _between functions, two NestedScale objects or their names.
map: A data.frame shaped like a scale_map() result: the two label columns named after the frames (or scales), plus n_from, n_overlap, w and w_from. NULL removes a previously registered map.

Value

Invisibly, the registry key. The get_ functions return the registered map (or NULL); list_scale_maps() a data.frame of registry keys.

Details

register_scale_map() and get_scale_map() handle a pair of frames of one scale; the map is scoped to that scale, so the same frame pair in two different scales does not collide. register_scale_map_between() and get_scale_map_between() handle a pair of scales.

Examples

s <- scale_example()
fake <- data.frame(
  class = "G1", group = "GC", n_from = 1L,
  n_overlap = 1L, w = 1, w_from = 1
)
register_scale_map(s, "class", "group", fake)
list_scale_maps()
#>                    key
#> 1 example:class->group
get_scale_map(s, "class", "group")
#>   class group n_from n_overlap w w_from
#> 1    G1    GC      1         1 1      1
register_scale_map(s, "class", "group", NULL) # remove
clear_scale_maps()