IMO if you want to hardcode a formula then simply hardcode a formula. If you 
want 20 formulas, write 20 formulas. Is that really so bad?

If you want to have an abbreviated way to specify sets of variables without 
conforming to R syntax then put them into data files and read them in using a 
format of your choice.

But using NSE to avoid using quotes for entering what amounts to in-script data 
is abuse of the language justified by laziness... the amount of work you put 
yourself and anyone else who reads your code through is excessive relative to 
the benefit gained.

NSE has its strengths... but as a method of creating data objects it sucks. 
Note that even the tidyverse (now) requires you to use quotes when you are not 
directly referring to something that already exists. And if you were... you 
might as well be creating a formula.

On January 4, 2021 11:14:54 PM PST, Steven Yen <st...@ntu.edu.tw> wrote:
>I constantly define variable lists from a data frame (e.g., to define a
>
>regression equation). Line 3 below does just that. Placing each
>variable 
>name in quotation marks is too much work especially for a long list so
>I 
>do that with line 4. Is there an easier way to accomplish this----to 
>define a list of variable names containing "a","c","e"? Thank you!
>
> > data<-as.data.frame(matrix(1:30,nrow=6))
> > colnames(data)<-c("a","b","c","d","e"); data
>
>   a  b  c  d  e
>1 1  7 13 19 25
>2 2  8 14 20 26
>3 3  9 15 21 27
>4 4 10 16 22 28
>5 5 11 17 23 29
>6 6 12 18 24 30
> > x1<-c("a","c","e"); x1 # line 3
>[1] "a" "c" "e"
> > x2<-colnames(subset(data,select=c(a,c,e))); x2 # line 4
>
>[1] "a" "c" "e"
>
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-- 
Sent from my phone. Please excuse my brevity.

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