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
