Real programs deal with failure all the time — files that don’t exist, network calls that time out, users who type letters where numbers were expected. Python’s exception handling is how we plan for those moments without crashing.

What’s in this section

1. What exceptions are — and how Python uses them
2. try and except — catching errors before they kill the program
3. Multiple exception types — handling each one differently
4. finally — code that runs no matter what
5. Raising exceptions — signal failure from your own code
6. Custom exception classes — make your errors meaningful
7. The with statement — automatic cleanup for files and resources

A well-handled exception is the difference between a polished program and one that crashes on day one.