pypsa-meets-earth/pypsa-earth

Address pandas 2.3 deprecations

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#1,715 opened on Feb 4, 2026

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Description

Describe the feature you'd like to see

pandas 3.0 has been released recently meaning that all deprecations of pandas 2.3 will become errors.

We have two following points to be addressed.

  1. Dedicated string data type by default This deprecation leads to the warning:

clean_osm_data.py:620: FutureWarning: Setting an item of incompatible dtype is deprecated and will raise an error in a future version of pandas. Value '['1.0' '1.0' '1.0' '1.0' '1.0' '1.0' '2.0' '2.0' '2.0' '1.0' '2.0' '1.0'

  1. Chained assignment has stopped working Which results in a warning in the solving script:

solve_network.py:661: FutureWarning: A value is trying to be set on a copy of a DataFrame or Series through chained assignment using an inplace method.The behavior will change in pandas 3.0. This inplace method will never work because the intermediate object on which we are setting values always behaves as a copy.

Contributor guide

Research direction
Locate the lines mentioned in the warnings (clean osm data.py:620 and solve network.py:661). For the string dtype deprecation, change the column assignment to use pandas.StringDtype() or ensure the column is of string type before assignment. For the chained assignment, replace inplace operations with direct assignment on the original DataFrame, or use .copy() and assign explicitly.
Tech stack
pythonpandas
Domain
databackend
Issue type
Refactor
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Pythonpandas
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65