KNN Algorithm in Machine Learning

If you are familiar with the concepts of machine learning and the basic algorithms used, you have probably heard of the k-nearest neighbour algorithm or KNN. In this article, I will tell you what the KNN algorithm in machine learning is and when to apply it in the machine learning process.

The KNN algorithm is one of the simplest techniques used in machine learning. It is a very simple algorithm that is preferred by many industry professionals due to its ease of use and reduced computing time.

Introduction to KNN Algorithm

In machine learning, KNN is an algorithm that ranks data points based on the points that most closely resemble it. It uses test data to make an informed estimate of the classification of an unclassified point.

KNN is an algorithm considered both nonparametric and an example of lazy learning. What exactly do these two terms mean?

  • Nonparametric means that it makes no assumptions. The model is made up entirely of the data given to it rather than assuming that its structure is normal.
  • Lazy learning means that the algorithm does not generalize. This means that there is little training involved when using this method. For this reason, all training data is also used in the tests when using KNN.

When To Use KNN Algorithm?

KNN can be used in both regression and predictive classification problems. However, when it comes to industrial problems, it is mainly used in classification because it corresponds to all the parameters evaluated when determining the usability of a technique.

  • Predictive power
  • Calculation time
  • Ease of interpretation of the output

The KNN algorithm corresponds to all the parameters of considerations. But above all, it is used because of its ease of interpretation and its reduced computing time.

Practical Implementation

Now you know the basics of one of the most basic machine learning algorithms. This is a great place to start when learning how to build models based on different sets of data. If you have a dataset with many different points and precise information, this is a great place to start exploring machine learning with KNN.

When looking to start using this algorithm, keep these three points in mind:

  • First, find a dataset that will be easy to work with, ideally one with many different points and labeled data.
  • Second, determine which language will be easiest for users to resolve the problem. 
  • Third, do your research. It is important to learn best practices for using this algorithm to find the most accurate results from your dataset.

You can learn about the practical implementation of KNN from here.


Various studies have been carried out on how this algorithm can be improved. These studies are intended to ensure that you can weigh the categories differently to make a more accurate classification. The weighting of these categories varies depending on how the distance is calculated.

In conclusion, this is a fundamental machine learning algorithm that is reliable for many reasons such as ease of use and fast computing time. It’s a good algorithm to use to start exploring the world of machine learning, but there is still room for improvement and modification.

I hope you like this article on the KNN algorithm in Machine Learning. Feel free to ask your valuable questions in the comments section below.

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Aman Kharwal
Aman Kharwal

I'm a writer and data scientist on a mission to educate others about the incredible power of data📈.

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