It is one of the popular and simplest classification and regression algorithm used in machine learning.
The k-Nearest Neighbors (KNN) algorithm is a supervised learning classifier.
The KNN algorithm can be used for both regression or classification problems but is generally used as a classification algorithm.
Since KNN algorithm heavily depend on memory to store all its training data, it is also referred to as an instance-based or memory-based learning algorithm .
It is commonly used for pattern recognition, data mining, financial market predictions, intrusion detection, etc….