As noted above, NumPy arrays behave a lot like other Python objects, for the sake of convenience. For instance, they can be indexed like lists; arr[0] accesses the first element of a NumPy array.

NumPy is known for being fast, but there's always room for improvement. Learn how to use Cython to iterate over NumPy arrays at the speed of C.

Building Random Arrays. NumPy has a few ways to build random number arrays. These methods are contained in the random library. In particular we will look at random.rand, random.randn, and ...