Python All-in-One For Dummies, 2nd Edition

Chapter 7

Sidestepping Errors

IN THIS CHAPTER

Discovering exceptions

Finding out how to handle errors gracefully

Making sure your app doesn't crash

Checking out try … except … else … finally

Learning to raise your own exceptions

We all want our programs to run perfectly all the time. But sometimes, situations in the real world stop a program from running. The problem isn't with you or your program. Usually, the person using the program did something wrong. Error handling is all about anticipating these problems, catching the error, and then informing users of the problem so they can fix it.

The techniques we describe here aren’t for fixing bugs in your code. You have to fix that type of error yourself. We’re talking strictly about errors in the environment in which the program is running, over which you have no control. Handling the error is simply a way of replacing the tech-speak error message that Python normally displays, which is meaningless to most people, with a message that ...