typelevel / typelevel/frameless

Provide a way to construct a `TypedColumn` reference from a Symbol

Open
#186 8 comments 0 reactions 0 assignees View on GitHub

@iravid is already working on this.

Since Sep 22, 2017.

  • #187 by @iravid — open
enhancement feature
Dominant language
Scala
Stars
895
Forks
135
Avg merge
1d 16h
Merged PRs (30d)
3

Description

Currently, we cannot chain selects that reference columns introduced in a select without introducing intermediate vals. Here's a (contrived) example:

case class X2(i: Int, j: Int)

val ds = TypedDataset.create(Seq(X2(10, 10))

ds.select(ds('i), ds('j), ds('i) + 1).select(ds('_3))

One possible solution for this would be to provide an overload to TypedDataset.select that uses Symbol arguments and a similar frameless.functions.col function.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the linked pull request 187 alongside the issue's chained TypedDataset.select example. Check the proposed TypedDataset.select overload and frameless.functions.col path, and confirm that the example can reference the newly introduced column without an intermediate val.

Written by the indexing model from the issue text.

Assessment

Tech stack
scala, spark
Domain
data-engineering
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
30/100

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