Understanding num_classes for xgboost in R

Question

I\'m having a lot of trouble figuring out how to correctly set the num_classes for xgboost.

I\'ve got an example using the Iris data

df <- iris

         


        

Answer 1

I had this problem and it turned out that I was trying to subtract 1 from my predictor which was already in the units of 0 and 1. Probably a novice mistake, but in case anyone else is running into this with a binary response variable that is already 0 and 1 it is something to make note of.

Tutorial said:

label = as.integer(iris$Species)-1

What worked for me (response is high_end):

label = as.integer(high_end)