Multiple legends in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of having multiple legends in a matplotlib plot?

Multiple legends help to clearly explain different groups or types of data in the same plot, making it easier to understand complex visuals.

intermediate

How do you create a second legend in matplotlib after the first one?

You create the first legend normally, then save its reference. For the second legend, you use ax.legend() again with different handles and labels, and add it to the axes with ax.add_artist().

intermediate

What does ax.add_artist() do in the context of multiple legends?

It adds the second legend as an artist to the axes, so both legends can appear on the same plot without replacing each other.

beginner

Why might you want to use multiple legends instead of combining all labels into one legend?

Multiple legends allow grouping related items separately, improving clarity when different data types or categories need distinct explanations.

beginner

Which matplotlib object typically holds the legend in a plot?

The legend is an artist object attached to the axes, often returned by ax.legend().

What function do you call to create a legend in matplotlib?

A ax.legend()

B plt.plot()

C ax.title()

D plt.show()

The ax.legend() function creates a legend for the plot.

How do you add a second legend to a matplotlib plot without removing the first?

A Call ax.legend() twice and use ax.add_artist() for the second

B Call plt.legend() twice only

C Use plt.show() twice

D Create two separate plots

You create the first legend normally, then add the second legend as an artist with ax.add_artist().

What does the handles parameter in ax.legend(handles=...) specify?

A The size of the plot

B The title of the plot

C Which plot elements to include in the legend

D The color of the plot lines

The handles parameter tells matplotlib which plot elements to show in the legend.

Why is it important to use ax.add_artist() when adding a second legend?

A To change the plot title

B To keep both legends visible on the same axes

C To remove the first legend

D To save the plot as an image

ax.add_artist() adds the second legend without replacing the first.

Which of these is NOT a reason to use multiple legends?

A To group different data categories separately

B To explain different plot elements distinctly

C To improve plot clarity

D To confuse the viewer

Multiple legends are used to clarify, not confuse, the plot.

Explain how to add multiple legends to a matplotlib plot and why it might be useful.

Think about how to keep both legends visible and why separate explanations help.

Describe the role of the handles and labels parameters when creating legends in matplotlib.

Handles and labels work together to define legend content.