rapidsai/cudf

[FEA] efficient way to truncate by month

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#18,650 opened on May 3, 2025

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 (5 comments) (0 reactions) (1 assignee)C++ (735 forks)batch import
Pythonfeature requestgood first issuelibcudf

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Description

Is there an efficient way to truncate a Series by month / quarter in cuDF?

https://docs.rapids.ai/api/cudf/latest/user_guide/api_docs/api/cudf.core.series.datetimeproperties.floor/ dt.floor doesn't support month / year / quarter

In pandas I can either, depending on the dtype backend:

  • drop to numpy and use astype('datetime64["3M"]'))
  • drop to PyArrow and use pc.floor_temporal

Any suggestion for cuDF?

Example: given

import cudf
from datetime import datetime

s = cudf.Series([datetime(2020, 2, 4)])
s.dt.truncate('3 months')  # Not valid syntax, I know :)

I'd like to end up with

'2020-01-01'

Contributor guide

Research direction
Examine the implementation of dt.floor in cuDF's source code (both Python and C++) to understand how truncation works for other frequencies. Then extend the functionality to support month, quarter, and year by following similar patterns. Refer to pandas' implementation for expected behavior.
Tech stack
python
Domain
backend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
PythonC++Git
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75