Multiple Axis with Plots.jl

Question

Is there a way to have the second dataset plot on a separate axis, overlaid on the first plot?

using Plots; gadfly(size=(800,400))

plot(Vector[randn(100)], line = ([:green], :step))

plot!(Vector[randn(100)], line = ([:red], :step))

Answer 1

It is now done by adding a twinx() argument:

plot(rand(10))
plot!(twinx(),100rand(10))

There is, however, some unintentional axis and label behavior:

1. Labels are plotted on top of each other by default
2. xticks are plotted on top of the already existing plot
3. Default colors are not correlated to the total number of series in the subplot

Therefore, I suggest adding some additional arguments:

plot(rand(10),label="left",legend=:topleft)
plot!(twinx(),100rand(10),color=:red,xticks=:none,label="right")

There still seems to be an issue correlating all series associated with the subplot at the moment.

Answer 2

It's easy, but doesn't work with Gadfly. It should work fine with PyPlot and GR. Here's an example:

Answer 3

If you have multiple series you want to plot and want to add your data incrementally, you can do it like this:

p = plot()
p_twin = twinx(p)

plot!(p,x,y)
plot!(p_twin,x,y_twin)

Answer 4

I can confirm (for GR) using Plots; gr()