[R] Including a large number of variables in a formula.

[peter dalgaard]

Two ideas:

nn <- names(wageszm14)
lvadd <- nn[grep("^lvacb", nn)]

or

lvadd <- paste0("lvacb", 23:81)
lvadd <- lvadd[lvadd %in% names(wageszm14)]

> On 5 Jun 2019, at 06:46 , Rolando I. Valdez via R-help <r-help using r-project.org> wrote:
> 
> Hello,
> 
> I have almost 40 variables that I am trying to include in a formula.
> 
> I tried to include them using as.formula(), however the variables do not
> follow a patter in the name. e.g. These variables are named like: lvacb23
> lvacb30 lvacb300  lvacb40 .....  lvacb81.
> 
>> lvadd <- paste0("lvacb", 23:81)
>> (fmla <- as.formula(paste("lwage ~ ", paste(lvadd, collapse = "+"))))
>> fit <- lm(fmla, data = wageszm14)
> Error in eval(predvars, data, env) : object 'lvacb24' not found
> 
> The variable lvacb24 doesn't exist, because from lvacb23 it jumps to
> lvacb30.
> 
> Thanks in advance for any help.
> -- 
> Rolando Valdez
> Facultad de Economía y Relaciones Internacionales
> Universidad Autónoma de Baja California
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
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