If you're interested in learning something like this, I highly recommend Udacity's deep learning nanodegree. They have a section that teaches you how to build y

If you're interested in learning something like this, I highly recommend Udacity's deep learning nanodegree. They have a section that teaches you how to build your own neural network with the the help of numpy. They even have a section where you write your own sentimental analysis neural network from scratch. Easily the best explanation and notebook to follow I have seen so far. I've been taking their revamped one that focuses on PyTorch rather than Tensorflow. Disclaimer: I am taking the deep learning nanodegree degree for free but its sponsored by Facebook rather than Udacity directly.