Renaming and transforming variables
julia
using AlgebraOfGraphics, CairoMakie
df = (x=rand(100), y=rand(100), z=rand(100), c=rand(["a", "b"], 100))
layers = linear() + mapping(color=:z)
plt = data(df) * layers * mapping(:x => (x -> x^2) => L"x^2", :y => L"This variable is called $y$")
fg = draw(plt)
Use a Tuple to pass combine several columns into a unique operation.
julia
plt = data(df) * layers * mapping(:x, (:x, :y, :z) => (+) => L"the new variable $x + y + z$", layout=:c)
fg = draw(plt)