Such resources are nice, certainly, they give a feel for what can be done. But in my experience you learn when you get your data loaded and start putting together code based on stackoverflow (or other) answers. Not by "dry-reading" someone else's work. There is no moment where you say: "I'll learn X now", there is a moment when X is the best solution to your problem en you start using it... and become an expert before you realize it. Imho.

Maybe it's different for you of course. And, I may have been in a nice position where I had a job that started to required X at some point. I realize that. But then maybe you can find a problem of your own (maybe you want to plot the data from your fitness tracker?) I once spend a lot of time plotting the details of my mortgage (cumulative paid, rent, decreasing dept as function of monthly payments), such data is just the result of some input and you make a table out of it yourself (in Excel if you want, in Pandas if you feel comfortable enough).