Feature: aggregations using custom user-defined functions #569
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR starts the work on enabling the use of custom, user defined functions (outside the scope of vaex) for doing aggregations.
I would also like to start a discussion regarding the support of aggregations using functions that require multiple columns (or expressions) as arguments, for example
df.x + df.y
calculated for each group. We also might want to extend this to include custom functions outside the scope of vaex.I guess such functions might take up memory, but can perhaps still be lazily evaluated?