The whole of numpy is based on arrays. You need to know numpy in order to do vector transformations in machine learning. Below are the links mentioned in the video.
/ vectors-in-machine-learning
http://www.scipy-lectures.org/intro/n...
https://www.tutorialspoint.com/numpy/...
https://stackoverflow.com/a/31181358/...
http://ml-cheatsheet.readthedocs.io/e...