Local imports

In Chapter 3, Using Modules and Packages, we introduced the concept of a global namespace, and showed how the import statement adds the name of the imported module or package into the global namespace. This description was actually a slight oversimplification. In fact, the import statement adds the imported module or package to the current namespace, which may or may not be the global namespace.

In Python, there are two namespaces: the global namespace and the local namespace. The global namespace is where all the top-level definitions in your source file are stored. For example, consider the following Python module:

import random
import string

def set_length(length):
    global _length
    _length = length

def make_name():
    global _length

    letters = []
    for i in range(length):
        letters.append(random.choice(string.letters))
    return "".join(letters)

When you import this Python module, you will have added four entries to the global namespace: random, string...