Python in a Nutshell

Chapter 8. Core Built-ins

The term built-in has more than one meaning in Python. In most contexts, a built-in is any object directly accessible to a Python program without an import statement. Chapter 7 showed the mechanism that Python uses to allow this direct access. Built-in types in Python include numbers, sequences, dictionaries, functions (covered in Chapter 4), classes (covered in Chapter 5), the standard exception classes (covered in Chapter 6), and modules (covered in Chapter 7). The built-in file object is covered in Chapter 10, and other built-in types covered in Chapter 13 are intrinsic to Python’s internal operation. This chapter provides additional coverage of the core built-in types, and it also covers the built-in functions available in module __builtin__.

As I mentioned in Chapter 7, some modules are called built-in because they are an integral part of the Python standard library, even though it takes an import statement to access them. Built-in modules are distinct from separate, optional add-on modules, also called Python extensions. This chapter documents the following core built-in modules: sys, getopt, copy, bisect, UserList, UserDict, and UserString. Chapter 9 covers some string-related core built-in modules, while Parts III and IV of the book cover many other useful built-in modules.

Built-in Types

This section documents Python’s core built-in types, like int, float, and dict. Note that prior to Python 2.2, these names referred to factory functions for creating ...