Where get_variables_where() gives the column names, this gives what
each of them means. Index by role to write a transformation that does
not care what the columns are called:
data[[get_axes(data)[["x"]]]].
Value
Named character vector: names are axis roles (x, y, z,
rho, phi, theta), values are the columns carrying them. Empty
for a frame whose coordinate system is "unknown".
See also
set_axes() to change it, get_variables_where() for the
columns without their roles.
Examples
af <- example_aniframe(n_obs = 3, n_individuals = 1, n_keypoints = 1)
get_axes(af)
#> x y
#> "x" "y"
df <- data.frame(time = 1:3, individual = "a", u = c(1, 2, 3), v = c(0, 1, 0))
renamed <- as_aniframe(df, variables_where = c(x = "u", y = "v"))
get_axes(renamed)
#> x y
#> "u" "v"
get_metadata(renamed, "coordinate_system")
#> [1] cartesian_2d
#> 7 Levels: unknown cartesian_1d cartesian_2d cartesian_3d polar ... spherical