Error in Math.factor(c(1L, 3L, 4L, : ‘round’ not meaningful for factors

Question

I always get this error: Error in Math.factor(c(1L, 3L, 4L, : 'round' not meaningful for factors for the following code:

C1<-train_data[,m]
  C2<-as.factor(C1)
  class_values<-C2

  train_data <- train_data[,-m]
  control <- trainControl(method="repeatedcv", number=5, repeats=1)
  train_model <-train(train_data,class_values,method='nb',trControl=control)

I tried to put: C2=as.factor(as.numeric(as.character(C1)), but not solved. C1 is numeric data from 1 to 5.

Answer 1

For rounding: you should either do:

df <- data.frame(a = factor(c(1.1,2.2,3.3)))
df$b = round(as.numeric(levels(df$a)[df$a]))

Or using data.table framework:

require(data.table)
setDT(df)
df[, b:= round(as.numeric(levels(a)[a]))]

After, we would need to see what is in your functions to know what's wrong... Hope it helps.