[Reinforcement Learning] Get started to learn Sarsa for reinforcement learning

If taking a look at Sarsa algorithm, you will find that it is so similar with Q-Learning.
For my previous post about Q-Learning, please refer to this link:
https://danny270degree.blogspot.com/2018/11/reinforcement-learning-get-started-to_21.html

Here is the Sarsa algorithm:

And, the main difference between Sarsa and Q-Learning is not much. Please compare with the following two graphs:
Q-Learning:

Sarsa:

We also consider Sarsa as on-policy strategy because the actor will adopt the action it picks up for the next state.Another difference is the epsilon-greedy policy for choosing actions.