KNN classifier in action

KNN.R

library(caret)
# Create training and test sets
set.seed(123)
trainIndex <- sample(c(FALSE,TRUE), size = nrow(dat), prob = c(.25,.75), replace = TRUE)
train_set <- dat[trainIndex, ]
test_set <- dat[!trainIndex, ]

# Learn KNN classifier
fit <- knn3Train(train_set %>% select(-y), test_set %>% select(-y), cl = train_set$y,
                 k = 3, prob = F)

tab <- table(actual = as.character(test_set$y), predicted = fit)
cm <- confusionMatrix(tab)
cm