Originally published on CodingCush .

Python error handling uses a try block to run risky code, an except block to catch and handle any error that happens, and a finally block for code that must run no matter what, such as closing a file. Instead of letting your whole programme crash with a red error message, you catch the problem, show a friendly message, and keep the rest of your code running safely.

What Is Error Handling in Python?

Every programme meets problems sooner or later. A user types letters where a number should go. A file you expected is missing. A network connection drops halfway through a download. In Python, these problems are called exceptions , and when one happens Python normally stops the programme and prints a long traceback — helpful for you as the developer, terrifying for your user.

Error handling is simply your plan for those moments. You tell Python: "Try this code, and if something goes wrong, do this instead of crashing." It is a bit like wearing a seatbelt.…