I am studying pygame and in the vast majority of tutorials it is said that one should run pygame.init() before doing anything. I was doing one particular tutorial and typing out the code as one does and noticed that in example after example there is no pygame.init() and no other explicit initialisation of any modules.

For instance, the following works (for me, at least) without any issues:

import pygamescreen = pygame.display.set_mode((600, 400))while True:for event in pygame.event.get():if event.type == pygame.QUIT:raise SystemExit

Just wondering how to find out exactly what is initialised when pygame.init() is run and what is initialised when pygame.init() is not run.

This will attempt to initialize all the pygame modules for you. Notall pygame modules need to be initialized, but this will automaticallyinitialize the ones that do.

http://www.pygame.org/docs/tut/ImportInit.html

I don't know what modules must be initialized, but it looks like display and event aren't in that category. I just recommend you to do it, because maybe some modules can work without being initialized but won't work the same way or they'll miss something important.