Here are some great videos from the University of Toronto's online Python course. I've taken this course, and the course (and the videos) are fantastic.
https://www.youtube.com/playlist?list=PLkHsKoi6eZnwpn7P5G8gEBebAY8Jbky4N
If I were to make a short list of videos to watch as a review or supplement to what we're doing in class, it would be:
Learn to Program The Fundamentals 2-3: Input Output and str Formatting
Learn to Program The Fundamentals 3-3: Converting between int, str, and float
Learn to Program The Fundamentals 4-2: str indexing and slicing
Learn to Program The Fundamentals 6-1: for loop over indices
Don't be intimidated by the number of videos I've listed here -- many of them are very short.