Defining partial list of variables

zx<-strsplit("age,exercise,income,white,black,hispanic,base,somcol,grad,employed,unable,homeowner,married,divorced,widowed",",")



On Tue, Jan 5, 2021 at 11:01 AM Steven Yen <styen at ntu.edu.tw 
<mailto:styen at ntu.edu.tw>> wrote:

    Thank you, Jeff. IMO, we are all here to make R work better to
    suit our
    various needs. All I am asking is an easier way to define variable
    list
    zx, differently from the way z0 , x0, and treat are defined.

    ?> zx<-colnames(subset(mydata,select=c(
    + age,exercise,income,white,black,hispanic,base,somcol,grad,employed,
    +???? unable,homeowner,married,divorced,widowed)))
    ?> z0<-c("fruit","highblood")
    ?> x0<-c("vgood","poor")
    ?> treat<-"depression"
    ?> eq1 <-my.formula(y="depression",x=zx,z0)
    ?> eq2 <-my.formula(y="bmi",?????? x=zx,x0)
    ?> eq2t<-my.formula(y="bmi",?????? x=zx,treat)
    ?> eqs<-list(eq1,eq2); eqs
    [[1]]
    depression ~ age + exercise + income + white + black + hispanic +
    ???? base + somcol + grad + employed + unable + homeowner + married +
    ???? divorced + widowed + fruit + highblood

    [[2]]
    bmi ~ age + exercise + income + white + black + hispanic + base +
    ???? somcol + grad + employed + unable + homeowner + married +
    ???? divorced + widowed + vgood + poor

    ?> eqt<-list(eq1,eq2t); eqt
    [[1]]
    depression ~ age + exercise + income + white + black + hispanic +
    ???? base + somcol + grad + employed + unable + homeowner + married +
    ???? divorced + widowed + fruit + highblood

    [[2]]
    bmi ~ age + exercise + income + white + black + hispanic + base +
    ???? somcol + grad + employed + unable + homeowner + married +
    ???? divorced + widowed + depression

    On 2021/1/5 ?? 04:18, Jeff Newmiller wrote:

    > 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 <styen at ntu.edu.tw

    <mailto:styen at 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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