# Filter with defaults for input array selection
**URL:** https://discourse.paraview.org/t/filter-with-defaults-for-input-array-selection/8343
**Category:** Development
**Tags:** python
**Created:** [November 5, 2021, 8:53pm UTC](https://discourse.paraview.org/t/filter-with-defaults-for-input-array-selection/8343 "2021-11-05T20:53:17Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@vadimcn](https://discourse.paraview.org/u/vadimcn)
#### Post date: [November 5, 2021, 8:53pm UTC](https://discourse.paraview.org/t/filter-with-defaults-for-input-array-selection/8343/1 "2021-11-05T20:53:17Z")
Hi,
I’d like to create a Python filter that transforms point coordinates of the input dataset using arrays from a secondary dataset. The secondary dataset is virtually always the same, and I’d like my plugin to have a default, so that users don’t need to configure array selection every time.
Something like: “If dataset xxx.vtk is loaded at filter creation time, use arrays yyy and zzz from that dataset”. Can this be done in ParaView?
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [November 8, 2021, 8:44am UTC](https://discourse.paraview.org/t/filter-with-defaults-for-input-array-selection/8343/2 "2021-11-08T08:44:32Z")
You can do something similar using a python filter/reader plugin, but what you are actually looking for may actually be a simple pvpython maccro that will look for the dataset and react accordingly.
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### Author:  [@vadimcn](https://discourse.paraview.org/u/vadimcn)
#### Post date: [November 9, 2021, 5:38pm UTC](https://discourse.paraview.org/t/filter-with-defaults-for-input-array-selection/8343/3 "2021-11-09T17:38:30Z")
> [@mwestphal](#):
>
> what you are actually looking for may actually be a simple pvpython maccro that will look for the dataset and react accordingly.
Right. What I’m struggling with is “What functions do I need to use to accomplish this?” I spent some time trying to figure out how to enumerate the currently loaded datasets and how to change my filter’s input port bindings via a script, but got lost in ParaView APIs ☹ Are there any examples/tutorials out there? (other than PythonAlgorithmExamples.py)
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [November 10, 2021, 8:58am UTC](https://discourse.paraview.org/t/filter-with-defaults-for-input-array-selection/8343/4 "2021-11-10T08:58:10Z")
Here is the documentation:
[https://kitware.github.io/paraview-docs/latest/python/index.html](https://kitware.github.io/paraview-docs/latest/python/index.html)