As a great example of the last point I LOVE this thing. https://doc.rust-lang.org/stable/rust-by-example/
Rust has an official book but it also has this list of runnable programs going over the features and usage.
So when I want to quickly see/remember a topic I can just look at it but if I want to learn inner workings in more detail to mess around with I can search it in the other documentation.