# Comparing two cases

**URL:** https://discourse.paraview.org/t/comparing-two-cases/6072
**Category:** ParaView Support
**Tags:** vtk, python
**Created:** [December 16, 2020, 11:22am UTC](https://discourse.paraview.org/t/comparing-two-cases/6072 "2020-12-16T11:22:23Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![metoman](https://discourse.paraview.org/user_avatar/discourse.paraview.org/metoman/32/5525_2.png) [@metoman](https://discourse.paraview.org/u/metoman)
#### Post date: [December 16, 2020, 11:22am UTC](https://discourse.paraview.org/t/comparing-two-cases/6072/1 "2020-12-16T11:22:23Z")

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Hello everyone,  
I need to compare two cases Cp distribution by extracting one to another. But when I try to use calculator, two case didn’t seem to get same calculator as variables. I am digging out for some python stuff but get nothing useful.  
Thanks in advance.

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### Author: ![bastian](https://discourse.paraview.org/user_avatar/discourse.paraview.org/bastian/32/7513_2.png) [@bastian](https://discourse.paraview.org/u/bastian)
#### Post date: [December 18, 2020, 6:09pm UTC](https://discourse.paraview.org/t/comparing-two-cases/6072/2 "2020-12-18T18:09:17Z")

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Try the programmable filter. It can have multiple inputs which would be your two sources of which you intend to get the difference.

[https://www.paraview.org/Wiki/Python\_calculator\_and\_programmable\_filter](https://www.paraview.org/Wiki/Python_calculator_and_programmable_filter)