Calculating datetime differences in Senaite (Bika) calculations appears to be problematic about senaite.core HOT 8 CLOSED

Hi @RML-IAEA: What is the problem here? Does the example above work or not?
BTW better ask configuration questions at https://community.senaite.org

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Hi grulisco, "It doesn't work at all. Datetime is not accepted in Senaite calculations

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Hi @RML-IAEA; I do not know how your datetime functions are working exactly. If the result of the expression is a string, it should work IMO.
Alternatively you can setup almighty "external calculations", see https://www.senaite.com/docs/analysis-calculations#external-calculations

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It only accepts float or integer values, not strings.

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Don't know then. Maybe your date result isn't a string yet.

We're working with calculated string expressions successfully.

Basically an entry like "This is a string" as calculation formula should return this string as result.

We have several cases like "This string" if [condition] else "Other string".

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How can you calculate the difference in days between datetimes inside the Senaite calculations section?

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see #2446 (comment)

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Simple datetime calcs work; try e.g. calculating number of days waiting for chrismas:
(datetime(2023,12,24)-datetime.today()).days

So the problem seems converting datetime data in a proper way.

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