Context manager

A context manager can be used to initialize and finalize resources. Once defined, they can be used with Python's with construct.

What is it?

context.py: illustrates two ways to define a context manager,

• as a class, providing hooks on instantiation, entering, and exiting the context.
• as function decorator, where code to be executed for initialization, entering, and exiting sandwiches a yield statement that returns the value.

Note

The exception is raised on purpose to illustrate exception handling by a context manager.