Concept of KNN Algorithm Using R 235
Published: 2020-08-29 09:00:48

Understanding the Concept of KNN Algorithm Using R 235
The huge amount of knowledge that we’re generating a day , has led to a rise of the necessity for advanced Machine Learning Algorithms. One such well-performed algorithm is that the K Nearest Neighbour algorithm.
In this blog on KNN Algorithm In R, we’ll understand what’s KNN algorithm in Machine Learning and its unique features including the pros and cons, how the KNN algorithm works, an essay example of it, and eventually moving to its implementation of KNN using the R Language.
It is quite essential to understand Machine Learning basics. Here’s a quick introductory section on what’s Machine Learning and its types.
Machine learning may be a subset of AI that gives machines the facility to seek out out automatically and improve from their gained experience without being explicitly programmed.
There are mainly three sorts of Machine Learning discussed briefly below:
Supervised Learning: it’s that a part of Machine Learning during which the info provided for teaching or training the machine is well labeled then it becomes easy to figure with it.
Unsupervised Learning: it’s the training of data employing a machine that’s unlabelled and allowing the algorithm to act thereon information without guidance.
Reinforcement Learning: it’s that a part of Machine Learning where an agent is put in an environment and he learns to behave by performing certain actions and observing the varied possible outcomes which it gets from those actions.
Now, moving to our main blog topic,
What is KNN Algorithm?
KNN which stands for K Nearest Neighbor may be a Supervised Machine Learning algorithm that classifies a replacement datum into the target class, relying on the features of its neighboring data points.
Let’s plan to understand the KNN algorithm with an essay example. Let’s say we would like a machine to differentiate between the sentiment of tweets posted by various users. to try to to this we must input a dataset of users’ sentiment(comments). And now, we’ve to coach our model to detect the emotions supported certain features. for instance , features like labeled tweet sentiment i.e., as positive or negative tweets accordingly. If a tweet is positive, it’s labeled as 1 and if negative, then labeled as 0.
Features of KNN algorithm:
KNN may be a supervised learning algorithm, supported feature similarity.
Unlike most algorithms, KNN may be a non-parametric model which suggests it doesn’t make any assumptions about the info set. This makes the algorithm simpler and effective since it can handle realistic data.
KNN is taken into account to be a lazy algorithm, i.e., it suggests that it memorizes the training data set instead of learning a discriminative function from the training data.
KNN is usually used for solving both classification and regression problems.
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Disadvantages of KNN algorithm:
After multiple implementations, it’s been observed that KNN algorithm doesn’t work with good accuracy on taking large datasets because the value of calculating the space between the new point and every existing points is large , and successively it degrades the performance of the algorithm.
It has also been noticed that performing on high dimensional data is sort of difficult with this algorithm because the calculation of the space in each dimension isn’t correct.
It is quite needful to perform feature scaling i.e., standardization and normalization before actually implementing KNN algorithm to any dataset. Eliminating these steps may cause wrong predictions by KNN algorithm.
Sensitive to noisy data, missing values and outliers: KNN is sensitive to noise within the dataset. we’d like to manually impute missing values and take away outliers.
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https://www.excelr.com/blog/data-science/machine-learning-supervised/understanding-the-concept-of-knn-algorithm-using-r