Class-Based vs Function-Based Context Managers

Nice explanation of Context Managers..:)

I like this as I only looked at it because I didn’t know what it was and now I understand!

You’re welcome, that’s great to hear :)

Detailing the various approaches in context really helps to understand the concept and how one might arrive at an implementation with respect to their own, or a community’s coding knowledge. The possible trouble of using an obscure approach since having its roots revealed is avoided by the awareness of what’s going on and how those who don’t know might get lost in an implementation that’s too far removed syntactically from the underlying logic. Without these videos even saying that would be impossible. Thanks for yet another insight.

Very nice tutorial which clearly explains the concept.

I wonder however how useful this is for database or socket connections which are usually ‘open’ for a longer time, especially sockets. Using this scheme every time you want to write/ read to a socket is probably very expensive. Is there a pattern to use here or is this just not the task for a ‘with’ statement?

finally understood the concepts, thanks :)

Please provide other examples where a context manager is useful besides dealing with files.

Nice to get an understanding of the context manager protocol and how some of the dunder methods work. Thank you for another great tutorial.

Great explanation of the generator and contextmanager.

Very interesting. Thanks Dan!

Nice work as always, Dan :)

Dan,

I understand the “obvious” vs “elegant” argument, but is there any behavioral or performance reason to prefer one approach over the other?

Thanks Paul

Great course; thanks Dan.

Hi Dan,

Many thanks for clear explanation. I understand that the with statement simplifies exception handling. But if an error occurs, what is the typical pattern for dealing with them (e.g. in database connections)? Put the with-statement in an additional try-except clause?

@michael That’s correct. The most common way to handle exceptions raised in a with clause would be to wrap the entire clause in another try..except clause:

try:
    with open(path) as file:
        pass  # Raise exception
except SomeException as ex:
    pass  # Handle the exception

I wish we had example on SQLite db.

@Pavneet Ghai what are you looking for regarding SQLite? Did you check out some the tutorials we have on it:

• Introduction to Python SQL Libraries
• Data Management With Python, SQLite, and SQLAlchemy