Chapter Summary

In this chapter, we covered the basics of modules, attributes, and imports and explored the operation of import statements. We learned that imports find the designated file on the module search path, compile it to byte code, and execute all of its statements to generate its contents. We also learned how to configure the search path to be able to import from directories other than the home directory and the standard library directories, primarily with PYTHONPATH settings.

As this chapter demonstrated, the import operation and modules are at the heart of program architecture in Python. Larger programs are divided into multiple files, which are linked together at runtime by imports. Imports in turn use the module search path to locate files, and modules define attributes for external use.

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Of course, the whole point of imports and modules is to provide a structure to your program, which divides its logic into self-contained software components. Code in one module is isolated from code in another; in fact, no file can ever see the names defined in another, unless explicit import statements are run. Because of this, modules minimize name collisions between different parts of your program.

You’ll see what this all means in terms of actual statements and code in the next chapter. Before we move on, though, let’s run through the chapter quiz.