Thanks a million, Milan!!!
Hongwei
On Tuesday, November 15, 2016 at 1:32:36 PM UTC-5, Milan Bouchet-Valat
wrote:
>
> Le lundi 14 novembre 2016 à 14:18 -0800, Hongwei Liu a écrit :
> > Hi guys,
> >
> > I am new to Julia and I have trouble in finding a similar function in
> > Julia that has the ability of "update" in R.
> >
> > For example, set formula = y ~ x1 + x2
> >
> > In R, I can use update(formula, D ~ . ) to change the formula from y
> > ~ x1 + x2 to D ~ x1 + x2
> >
> > In Julia, the formula's type is DataFrames.Formula and I have
> > searched online and Dataframes document for a long time but still
> > couldn't find the answer.
> >
> > So my question is:
> >
> > Is there are such a function in Julia? If not, is there a way to
> > modify a formula directly?
> I don't think we provide such a function yet, but you can easily do
> that manually.
>
> Use dump() to see what the formula object consists in:
> julia> dump(y ~ x1 + x2)
> DataFrames.Formula
> lhs: Symbol y
> rhs: Expr
> head: Symbol call
> args: Array{Any}((3,))
> 1: Symbol +
> 2: Symbol x1
> 3: Symbol x2
> typ: Any
>
> Here, you can just change the rhs (right hand side) argument:
> julia> f = y ~ x1 + x2
> Formula: y ~ x1 + x2
>
> julia> f.lhs = :D
> :D
>
> julia> f
> Formula: D ~ x1 + x2
>
>
> Regards
>
> > Thanks a lot!!
> >
> > Hongwei
>
