[ghaff]

For the most part, presentations aren't a great format for getting into a lot of details in things like code and they generally shouldn't even try. They're much better for making you aware of potentially interesting things and highlight how you might use them. (It's also why I find most presentations are better when they're shorter.)

As others have said as well, if you're going to a meetup to do the equivalent of attending a lecture, you're probably not going to find them very valuable.