JuliaData / JuliaData/DataFramesMeta.jl
Allow reference to previously defined columns in @transform
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- Dominant language
- Julia
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- 496
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Description
This might be too big of an ask, but in dplyr we can do this
data.frame(x=c(1,2,3)) %>% mutate(y=2*x, z=y+2)
that is, defining z and then using it in the same mutate call.
But is not possible with @transform. It would be very nice to be able to do
@transform DataFrame(x=[1,2,3]) begin
:y = :x .* 2
:z = :y .+ 2
end
Is there a reason this isn't supported?
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by tracing the @transform macro and how expressions in a single transform block are evaluated. Confirm the desired behavior using the issue's x, y, and z example, then define completion as allowing z to reference the newly defined y while preserving existing transform behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- julia
- Domain
- data
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100