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Problems using select() with pandas 3.0.0 #76
Description
What happened?
Hi,
I have noticed an issue when using pandas 3.0.0 and using select() on a fieldset. It was no longer possible to select fields based on endStep (returned fieldset was None) while selecting using shortName and step worked fine. If I explicitly work with pandas 2.3.3 this problem does not arise.
Maybe this actually applies to all keys which are not part of the standard set (e.g. listed with ls()), but I didn't test that yet.
Best regards
Dennis
What are the steps to reproduce the bug?
new = mv.regrid(data=f.select(shortName=parameter, endStep=step), grid=[2, 2])
pip install metview pandas==2.3.3
--> works
pip install metview pandas==3.0.0
--> doesn't work
Version
v1.16.2
Platform (OS and architecture)
Linux b1548b5f5c57 6.12.67-linuxkit #1 SMP Sun Jan 25 02:26:28 UTC 2026 aarch64 aarch64 aarch64 GNU/Linux
Relevant log output
Accompanying data
No response
Organisation
MeteoIQ GmbH
Activity
iainrussell commentedon Feb 16, 2026
Hi @snow73,
Thanks for reporting this! I can reproduce it. It seems that pandas 3.0 is stricter in type-checking. We have a set of pre-defined keys with their preferred types (int/str/etc) - step is in there, but endStep is not. The quick workaround is to change your query to put quotes around your endStep value to make it a string:
step="90". If you think this will be a problem, we can look at making endStep an int by default.snow73 commentedon Feb 18, 2026
Hi @iainrussell, no worries, I have downgraded to pandas 2.3.3 for the time being. Thanks for pointing out the workaround!