Reinforcement learning is an area in Machine Learning which is quite different than supervised or unsupervised learning. This is because it is not about building a model based upon a dataset with given features and label(s). It is about software agents that take actions in a certain environment to maximize a reward. It has applications in game theory, operations research, genetic algorithms. It is also used in something that is changing the way we will transport ourselves in the future..self driving cars!
As part of my Machine Learning study, I have used reinforcement learning to create an agent for a self driving car. Please see my github.