Context Managers

Part of the Python course

Welcome back. Ever since lesson 09 you have been writing with open(...) as f: and trusting that the file gets closed when the block ends. This lesson opens that box. You will learn what the with statement actually does, and how to write your own context managers so any setup-and-teardown pair you have can ride on the same syntax.

Open main.py in the editor. The file uses a small context manager called timer to measure how long a block of code takes, then prints it. Click the play button. You should see something close to: