knn

Syntax

knn(Y, X, type, nNeighbor, [power=2])

Arguments

Y is a vector with the same length as the number of rows of X. Each element is a label corresponding to each row in X.

X is a table. Each row is an observation and each column is a feature.

type is a string. It can be either “regressor” or “classifier”.

nNeighbor is a positive integer indicating the number of nearest neighbors in training.

power is a positive integer indicating the parameter of Minkowski distance used in training. The default value is 2 indicating Euclidean distance. If power=1, it means Manhattan distance is used in training.

Details

Inplement the k-nearest neighbors algorithm (k-NN) for classification and regression. Return a dictionary with the following keys:

  • nNeighbor: the number of nearest neighbors in training.

  • modelName: string “KNN”.

  • model: the model to be saved.

  • power: the parameter of Minkowski distance used in training.

  • type: “regressor” or “classifier”.

Examples

$ height = 158 158 158 160 160 163 163 160 163 165 165 165 168 168 168 170 170 170
$ weight = 58 59 63 59 60 60 61 64 64 61 62 65 62 63 66 63 64 68
$ t=table(height, weight)
$ labels=take(1,7) join take(2,11)
$ model = knn(labels,t,"classifier", 5);