Working with Libraries

Working with external libraries in Python makes use of the import keyword. While this can go anywhere in your file, it’s almost always best to import libraries at the top of each file where they’re used. For example, in the last section, we were able to call upon the built-in json library by calling import json at the top of our code.

Importing modules with the import keyword is usually the best method, because it preserves the module’s namespace. However, you can also use the from <module> import <object> syntax to import a specific object (function, variable, subclass, etc.) from a module into your program’s namespace.

For example, if we wanted a random integer between 0 and 100, we could use random.randint():

>>> import random
>>> random.randint(0, 100)

Notice that the namespace is preserved (we needed to call random.randint()). If we use from instead:

>>> from random import randint
>>> randint(0, 100)

Installing the requests library with pip

For the next chapter, we’ll be using an excellent 3rd part library called requests to make light work of retrieving data from web APIs. To install the requests library, run this on your command line:

(env) $ python -m pip install requests

This runs the pip module and asks it to find the requests library on (the Python Package Index) and install it in your local system, so that it becomes available for you to import. We’ll dive a little more into this later.