library(bnlearn)
discretize(train, method = "quantile", breaks = 2)

discretize(test, method = "quantile", breaks = 2)

training_data <- runif(100)
test_data <- runif(100)
breaks_to_use <- quantile(training_data, seq(0, 1, 0.25))
discretized_training_data <- cut(training_data, breaks = breaks_to_use)
discretized_test_data <- cut(test_data, breaks = breaks_to_use)

library(arules)

train <- data.frame(dat = runif(100))
test <- data.frame(dat = runif(100))

mastercuts <- arules::discretize(train, method = "interval", categories = 4, onlycuts = T)

train$bin <- as.numeric(cut(train, breaks = mastercuts))