Getting Matplotlib's colors in order

Matplotlib can be very easy to use at times, especially if you just want to make a simple "y vs. x" type of plot. But when it comes to specialized customization, it can be a bit challenging to find the proper solution. The situation is not helped by the fact that a lot of times, an obscure answer on Stack Overflow no longer works because the API changed.

One common need is to color things in the same way. For example, say you want to plot two dependent variables with widely different scales that share an independent variable. This is often represented by having two separate vertical axes which are colored to match the lines or markers of each data set. The most basic approach is to manually assign colors for the lines and axes, but if using a custom style, such as the ggplot style, we need a way to access the color cycle used if we want to remain consistent with the selected style. Here is the best way I have found which works at least in version 1.5:

colors = plt.rcParams["axes.prop_cycle"].by_key()["color"]

colors should now be a list which contains the colors defined in order by the current style.

more ...