How to make an arbitrary large number of variables be treated as factors

Question

I have a large amount of variables that I must treat as categorical although they are represented numerically. For one variable I know I can use

train$var1 = as.factor(train$var1)

But how can I apply the same for as many variables as I want?

If you want to apply it to _all_ columns (variables), you can do `train[] <- lapply(train, as.factor)` — talat, Dec 26 '15 at 21:08

score 3 · Accepted Answer · answered Dec 26 '15 at 21:09

3

If you want to apply it to all columns (variables), you can do

train[] <- lapply(train, as.factor)

or for a subset of columns (for example 3 to 10) use

train[3:10] <- lapply(train[3:10], as.factor)

answered Dec 26 '15 at 21:09

talat

1 Answers1