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

[Sören Vogel]

`model.matrix` was what I was looking for.

Thanks,
Sören

> On 28.03.2017, at 16:57, peter dalgaard <pdalgd at gmail.com> wrote:
> 
> 
>> 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
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Office: A 4.23
> Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com
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