DEPR: make Series.agg aggregate when possible by topper-123 · Pull Request #53325 · pandas-dev/pandas (original) (raw)

The doc string for Series.agg says: "A passed user-defined-function will be passed a Series for evaluation." which isn't true currently. In addition, Series.agg currently will not always aggregate, when given a aggregation function. This PR fixes those issues.

It can be noted that both the behavior and that doc string are correct for DataFrame.agg, so this PR aligns the behavior of Series.agg and DataFrame.agg.

I'm not sure if this is too drastic as a bug fix, or we want it as part of a deprecation process, but just putting this up there, will see where it goes.

EDIT: In the new version the old behavior is deprecated rather than just removed.