[R] How to apply calculations in "formula" to "data frame"

[peter dalgaard]

> On 28 Mar 2017, at 16:14 , Sören Vogel <soeren.vogel at posteo.ch> wrote:
> 
> Hello
> 
> Ho can I apply a formula to a data frame?


That would depend on whether the formula has any special interpretation.

If if is just an elementary expression, then it would be like 

eval(For1[[3]], Data, environment(For1))

but you are using "." to represent... what exactly?

One possibility is model.matrix(For1, Data)

but I'm not at all sure that that is what you want.

-pd

> 
> library("formula.tools")
> Data <- data.frame("v1" = rnorm(31), "v2" = runif(31), "v3" = sample(1:7, 31, repl=T), "v4" = rlnorm(31))
> For1 <- as.formula(v1 ~ .^3)
> Lhs <- Data[, formula.tools::lhs.vars(formula)]
> Rhs <- apply_formula_to_data_frame_and_return_result(data, formula) # ???
> 
> Thank you,
> Sören
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
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