13.3.1 Introduction

Python comes with many different libraries by default. You may also want to install more of those for specific purposes, such as optimization, plotting, reading/writing file formats, image handling, and so on. NumPy and SciPy are two important examples of such libraries, Matplotlib for plotting is another one. At the end of this chapter, we will list some useful libraries.

To use a library, you may either

• load only certain objects from a library, for example, from NumPy:

from numpy import array, vander

• load the entire library:

from numpy import *

• or give access to an entire library by creating a namespace with the library name:

import numpy
...
numpy.array(...)

Prefixing a function from the library with the namespace gives access to this function and distinguishes this function from other objects with the same name.

Furthermore, the name of a namespace can be specified together with the import command:

import numpy as np
...
np.array(...)

Which...