Reservoir Sampling

Reservoir Sampling Reservoir sampling is a technique for selecting a fair random sample when you don't know the size of the set you're sampling from. By the end of this essay you will know: When you would need reservoir sampling. The mathematics behind how it works, using only basic operations: subtraction, multiplication, and division. No math notation, I promise. A simple way to implement reservoir sampling if you want to use it. Before you scroll! This post has been sponsored by the wonderful folks at ittybit, and their API for working with videos, images, and audio. If you need to store, encode, or get intelligence from the media files in your app, check them out! # Sampling when you know the size In front of you are 10 playing cards and I ask you to pick 3 at random. How do you do it? The first technique that might come to mind from your childhood is to mix them all up in the middle. Then you can straighten them out and pick the first 3. You can see this happen below by cl ... Read full article.