There are many great tutorials on neural networks that one can find online nowadays. Simply searching for the words “Neural Network” will produce numerous results on GithubGist. Even tough there are many examples floating around on the web, I decided to have my own Introduction to Neural Networks!
In my tutorial, I specifically tried to illustrate the use of Python classes to define layers in the network as objects. Each layer object has forward and backward propagation methods which leads to compact, easily readable code.
Here is the Python notebook of Yet another introduction to neural networks. Below is an extract (picture.) Hopefully you will enjoy!