Plotting in Pluto

It’s super easy to create plots in Pluto! There are many plotting libraries for Julia, and most will work well with Pluto.

Plots.jl

Plots.jl is an easy-to-use plotting library for Julia. It is a versatile plotting library, with a syntax that is similar to Python’s Matplotlib. To use it in Pluto, you add the following code to your notebook:

using Plots

plot([4,5,8,2,3,1,0])

Larger code blocks

You often want to combine multiple plot calls in a single cell. The let block is really useful for this! Here is an example:

data = rand(100)::Vector{Float64}

let
    plot(data)

    # use the ! explamation mark to modify the previous plot
    scatter!(data)

    # add a horizontal line
	mean = sum(data) / length(data)
	hline!([mean]; label="Average value")
end

Using a let block instead of begin means that the variables defined in the block are local to the block, and they will not affect the rest of the notebook. In this example, the mean variable is only defined inside the let block, not in other cells.

My plot is not showing!

Sometimes, you create a plot in your code, but you don’t see it. This is because Pluto displays the last output of a cell . The plot function “creates a plot”, but it only gets displayed if the cell output is that object.

For example, this code will not show a plot:

let
    x = 1:10
    y = rand(10)
    
    plot(x, y, label="Data points")
    
    for i in 1:length(x)
        scatter!([x[i]], [y[i]], label="Point $i")
    end
end

This is because the last expression in the let block is a for loop, which returns nothing. (So nothing will be displayed.)

To fix it, add a plot!() call at the end of the cell. This will get the current plot, and just return it.

let
    x = 1:10
    y = rand(10)
    
    plot(x, y, label="Data points")
    
    for i in 1:length(x)
        scatter!([x[i]], [y[i]], label="Point $i")
    end

    # ✅ This is the fix!
	plot!()
end

Take a look at the Plots.jl featured notebook to learn more!

Makie.jl

Makie.jl is a powerful plotting library for Julia. It is built on top of the Julia plotting ecosystem and provides a simple interface for creating plots.

Not all Makie backends work well with Pluto. The best option is to use the GLMakie or CairoMakie backend. To see an example, take a look at this featured notebook:

Plotly

You can use the Plotly JS plotting library in Pluto! Check out the PlutoPlotly.jl package to get started.

More libraries

There are more (experimental) plotting libraries for Julia. They probably work with Pluto, try them out!