[R] Apply as.factor (or as.numeric etc) to multiple columns

[Mark Na]

Hi R-helpers,

I have a dataframe with 60columns and I would like to convert several
columns to factor, others to numeric, and yet others to dates. Rather
than having 60 lines like this:

data$Var1<-as.factor(data$Var1)

I wonder if it's possible to write one line of code (per data type,
e.g. factor) that would apply a function (e.g., as.factor) to several
(non-contiguous) columns. So, I could then use 3 or 4 lines of code
(for 3 or 4 data types) instead of 60.

I have tried writing an apply function, but it failed.

Thanks for any help you might be able to provide.

Mark Na