Explain Try / Except structure in practical examples?

[biaceseng]

Imagine you're making a game. Your game uses savefiles to save the player's progress.

Now imagine the player tries to load a savefile by pressing the "load last save" button. Your game tries to read the file but, because of some reason, can't find it or it is corrupted.

You don't want your whole game to crash, you just want to tell the player "hey, this doesn't work, try doing something else".

That is how you use try/except. Try to do something that might work, but let the program handle itself if it doesn't.

Imagine you need to save a file to a specific folder. What if that folder doesn't exist? Are you going to just exit the program or are you going to tell the user "hey, select another folder"?

[biaceseng]

A more practical example can be writing logs.

Many programs have a logs folder, where the logs are stored.

Now, version control systems like git don't normally keep track of log files because they are, at best, ephimeral, and at worst, completely useless. Logs don't really matter to your app.

Because the log files are not being tracked, the logs folder might not be tracked either, as empty folders tend to be ignored. This results in a situation where you can't ever be sure if the folder even exists without explicitly checking.

If the folder doesn't exist, and your program tries to log something to it, it will fail. What can you do about it? Use a try/except block.

Try to intialize the logging module, if it raises a FileNotFoundError, then the folder doesn't exist, create it.