[R] repeating the same variable in formula
Subirana Cachinero, Isaac
i@ubir@n@ @ending from imim@e@
Mon Dec 10 11:35:03 CET 2018
Thank you for your response.
In fact, I use the formula environament to select variables, as part of the code of another function.
I would like to allow the user to select the same variable more than once.
The use of I() may partly solve the problem. However, I would like attr(terms(g),"term.labels") would return a vector with as many components as variables including repetitions. And using I() function, there would be some work remaining to split "I(age + age)" into "age", "age", taking into account that in other examples variable may include white spaces or other characters within ` `.
Isaac.
-----Mensaje original-----
De: Rui Barradas [mailto:ruipbarradas using sapo.pt]
Enviado el: lunes, 10 de diciembre de 2018 11:27
Para: Subirana Cachinero, Isaac; r-help using r-project.org
Asunto: Re: [R] repeating the same variable in formula
Hello,
The formulas
y ~ cholesterol + age + age
and
y ~ cholesterol + age
are the same formula.
If you want 'age' twice, maybe
g <- y ~ cholesterol + I(age + age)
attr(terms(g), "term.labels")
#[1] "cholesterol" "I(age + age)"
Hope this helps,
Rui Barradas
Às 06:49 de 10/12/2018, Subirana Cachinero, Isaac escreveu:
> y ~ cholesterol + age + age
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