Add columns to a chart's tooltip — set

Names extra columns to show when a mark is hovered, alongside x and y. Name an argument to label it, or pass a bare column name to label it with the column name. A column mapped with set_color() is added for you.

Usage

set_tooltip(chart, ...)

Arguments

chart: Defines which chart to modify.
...: Defines which columns to show, as bare column names. Name an argument to use that name as the label. Passing none clears whatever is already set.

Value

chart, with its tooltip fields set.

Details

Every mark on a chart covers a group of rows: a bar covers every row with that x, a heat cell every row in that pair of categories. An extra field can only be shown when it takes a single value across that group, so set_tooltip() checks that and errors rather than pick one arbitrarily. Histograms are the exception and take no tooltip fields at all, because their bins are computed in the browser.

Examples

df <- data.frame(len = c(1, 5, 3), dep = c(2, 4, 6), id = c("a", "b", "c"))

arc_scatter(df, len, dep) |>
  set_tooltip(Identifier = id)