Grokking Algorithms, Second Edition

12 k-nearest neighbors

In this chapter

• You learn to build a classification system using the k-nearest neighbors algorithm.
• You learn about feature extraction.
• You learn about regression: predicting a number, like the value of a stock tomorrow or how much a user will enjoy a movie.
• You learn about the use cases and limitations of k-nearest neighbors.

Classifying oranges vs. grapefruit

Look at this fruit. Is it an orange or a grapefruit? Well, I know that grapefruits are generally bigger and redder.

My thought process is something like this: I have a graph in my mind.

Generally speaking, the bigger, redder fruit are grapefruits. This fruit ...