# Datetime, arithmetic operations

**URL:** <https://forum.inductiveautomation.com/t/datetime-arithmetic-operations/79314>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [September 18, 2023, 8:23pm UTC](https://forum.inductiveautomation.com/t/datetime-arithmetic-operations/79314 "2023-09-18T20:23:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![rigoberto.reyes](https://avatars.discourse-cdn.com/v4/letter/r/65b543/32.png) [@rigoberto.reyes](https://forum.inductiveautomation.com/u/rigoberto.reyes)\
**Post date:** [September 18, 2023, 8:23pm UTC](https://forum.inductiveautomation.com/t/datetime-arithmetic-operations/79314/1 "2023-09-18T20:23:17Z")

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Hi there.

![imagen](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/0/9076c1d17264ff5679b4a7102ff7431ba4bf7e3e.png)

I´m using a power table object to show datetime data and I need to know the difference (substract) in minutes between first and second row, second and third row, etc. I set **Extensions Function/ configurecell** to do it, using libraries:

from datetime import datetime  
from datetime import timedelta

However there is a mistake, maybe because power table is considering datetime column as string instead of datetime data type.

How can I solve this issue?

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [September 18, 2023, 8:38pm UTC](https://forum.inductiveautomation.com/t/datetime-arithmetic-operations/79314/2 "2023-09-18T20:38:13Z")

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Ignition uses java datatypes, not jython datatypes. So jython's `datetime` module screws up. Use `system.date.*` scripting functions instead.