Kaggle has an amazing set of courses with well organised content over here: https://www.kaggle.com/learn/overview
I just finished the Python micro-course (https://www.kaggle.com/learn/python), and I wanted to tell folks that it's worth your time! I've done some Rails programming before, but majority of my recent work was in JS (and PHP before that), so I needed a quick intro.
I tried learning Python a couple times via the Python website, but it just wasn't as ergonomic as this free Kaggle course. It can be literally completed in 4-5 hours, has lots of humour peppered in which kept it really entertaining, and Python is a rather nice language :-D