Basic Parallel Coordinates Plot

Mix.install([
  {:plotly_ex, "~> 0.3"},
  {:kino, "~> 0.18"}
])

Section

line: %{color: [...], colorscale: "..."} colours each line by a numeric variable. Provide one colour value per observation (same length as each values list). A colour bar appears automatically.

alias Plotly.{Figure, Parcoords}

# 8 Iris observations: 0=setosa, 1=versicolor, 2=virginica
species = [0, 0, 0, 0, 0, 1, 1, 2]

Figure.new()
|> Figure.add_trace(
  Parcoords.new(
    dimensions: [
      %{label: "Sepal Length", values: [5.1, 4.9, 4.7, 5.0, 5.4, 6.3, 5.8, 7.1]},
      %{label: "Sepal Width",  values: [3.5, 3.0, 3.2, 3.6, 3.9, 3.3, 2.7, 3.0]},
      %{label: "Petal Length", values: [1.4, 1.4, 1.3, 1.4, 1.7, 4.7, 5.1, 5.9]},
      %{label: "Petal Width",  values: [0.2, 0.2, 0.2, 0.2, 0.4, 1.6, 1.9, 2.1]}
    ],
    line: %{
      color: species,
      colorscale: [[0, "purple"], [0.5, "lightseagreen"], [1, "gold"]],
      showscale: true,
      cmin: 0,
      cmax: 2
    }
  )
)
|> Figure.update_layout(title: "Parallel Coordinates — Coloured by Species")
|> Plotly.show()