Woah! You've covered a lot on NumPy. And that's why these extra resources are optional. You can think of them as supplements to what we've covered so far.

I learn best when I look at similar things from different angles.

In this case, that's what these extra resources on NumPy provide. A look at the material we've covered from different points of view.

• The Basics of NumPy Arrays by Jake VanderPlas

• A Visual Introduction to NumPy by Jay Alammar

• NumPy Quickstart tutorial (part of the NumPy documentation)

As always, remember the best way to learn a new coding concept is to write it yourself. If in doubt, run the code.