Chapter 14. Exceptions
This chapter discusses exceptions, which are language features specifically aimed at handling unusual circumstances during the execution of a program. The most common use for exceptions is to handle errors that arise during the execution of a program, but they can also be used effectively for many other purposes. Python provides a comprehensive set of exceptions, and new ones can be defined by users for their own purposes.
The concept of exceptions as an error-handling mechanism has been around for some time. C and Perl, the most commonly used systems and scripting languages, don’t provide any exception capabilities, and even programmers who use languages such as C++, which does include exceptions, are often unfamiliar with them. This chapter doesn’t assume familiarity with exceptions on your part but instead provides detailed explanations.
The following sections provide an introduction to exceptions and how they’re used. If you’re already familiar with exceptions, you can skip directly to “Exceptions in Python” (section 14.2).