astronomy-commons / astronomy-commons/lsdb

Add Catalog.eval() method

Open
#606 2 comments 0 reactions 0 assignees View on GitHub
documentation enhancement question
Dominant language
Python
Stars
55
Forks
26
Avg merge
4d 1h
Merged PRs (30d)
8

Description

**Feature request**

`pd.DataFrame.eval` is a useful tool for creating new columns and manipulating column data safely. While it supports a limited set of functionalities, it is particularly helpful for adding new columns to a `Catalog`—a feature that is currently accessible only through `Catalog.map_partitions` and `Catalog.assign`.

It is supported by `nested-pandas`, but not `nested_dask` yet:
https://github.com/lincc-frameworks/nested-dask/issues/63

**Before submitting**
Please check the following:

- [x] I have described the purpose of the suggested change, specifying what I need the enhancement to accomplish, i.e. what problem it solves.
- [ ] I have included any relevant links, screenshots, environment information, and data relevant to implementing the requested feature, as well as pseudocode for how I want to access the new functionality.
- [ ] If I have ideas for how the new feature could be implemented, I have provided explanations and/or pseudocode and/or task lists for the steps.

Contributor guide

No contributing guide indexed for this repository

Research direction

Start by comparing the existing Catalog.map_partitions and Catalog.assign APIs with the nested-pandas support for DataFrame.eval, using the linked nested_dask issue as context. Done means Catalog exposes eval() for creating new columns and manipulating column data as described, with behavior consistent with the supported functionality.

Written by the indexing model from the issue text.

Assessment

Tech stack
pandas, python
Domain
data
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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