Python context Manager

The so-called context manager is the class that implements the context Management Protocol (implementing the __enter__ and __exit__ methods) or functions (using the ContextManager adorner).

The context manager is used in some special scenarios where a typical scenario is to open a resource to process the resource and then close the resource. As you can see, the context manager acts like a common try/finally statement by ensuring that open resources are closed in a timely manner, regardless of the circumstances.

, but the context manager should be preferred, because the context manager can do the same work with less code.

1 with statement

with expression [as variable]:  with-blockwith open ('data.txt'  ) as F:  print(f.read)

Python context Manager