This chapter begins our tour of the Python language. In an informal sense, in Python we do things with stuff.^[11] “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 can do with it.

Somewhat more formally, in Python, data takes the form of objects—either built-in objects that Python provides, or objects we create using Python classes or external language tools such as C extension libraries. Although we’ll firm up this definition later, objects are essentially just pieces of memory, with values and sets of associated operations. As we’ll see, everything is an object in a Python script. Even simple numbers qualify, with values (e.g., 99), and supported operations (addition, subtraction, and so on).

Because objects are also the most fundamental notion in Python programming, we’ll start this chapter with a survey of Python’s built-in object types. Later chapters provide a second pass that fills in details we’ll gloss over in this survey. Here, our goal is a brief tour to introduce the basics.