Python in a Nutshell, 3rd Edition

Chapter 10. File and Text Operations

This chapter covers most of the issues related to dealing with files and filesystems in Python. A file is a stream of text or bytes that a program can read and/or write; a filesystem is a hierarchical repository of files on a computer system.

Other Chapters That Also Deal with Files

Because files are such a crucial concept in programming, even though this chapter is the largest one in the book, several other chapters also contain material that is relevant when you’re handling specific kinds of files. In particular, Chapter 11 deals with many kinds of files related to persistence and database functionality (JSON files in “The json Module”, pickle files in “The pickle and cPickle Modules”, shelve files in “The shelve Module”, DBM and DBM-like files in “The v3 dbm Package”, and SQLite database files in “SQLite”), Chapter 22 deals with files and other streams in HTML format, and Chapter 23 deals with files and other streams in XML format.

Organization of This Chapter

Files and streams come in many flavors: their contents can be arbitrary bytes or text (with various encodings, if the underlying storage or channel deals only with bytes, as most do); they may be suitable for reading, writing, or both; they may or may not be buffered; they may or may not allow “random access,” going back and forth in the file (a stream whose underlying channel is an Internet socket, for example, only allows sequential, “going forward” access—there’s no “going back ...