Is Python a

Chapter 4CHAPTER 4Introducing Python Object Types4This chapter begins our tour of the Python language. In an informal sense, in Python,we do things with stuff. “Things” take the form of operations like addition and concatenation,and “stuff” refers to the objects on which we perform those operations.In this part of the book, our focus is on that stuff, and the things our programs cando with it.Somewhat more formally, in Python, data takes the form of objects—either built-inobjects that Python provides, or objects we create using Python or external languagetools such as C extension libraries. Although we’ll firm up this definition later, objectsare essentially just pieces of memory, with values and sets of associated operations.Because objects are the most fundamental notion in Python programming, we’ll startthis chapter with a survey of Python’s built-in object types.By way of introduction, however, let’s first establish a clear picture of how this chapterfits into the overall Python picture. From a more concrete perspective, Pythonprograms can be decomposed into modules, statements, expressions, and objects, asfollows:1. Programs are composed of modules.2. Modules contain statements.3. Statements contain expressions.4. Expressions create and process objects.The discussion of modules in Chapter 3 introduced the highest level of this hierarchy.This part’s chapters begin at the bottom, exploring both built-in objects and theexpressions you can code to use them.65