Python equivalent of C++ pass by reference

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Here is an example of a C++ function using pass by reference (non-const pointer arguments): vtkMRMLAnnotationsROINode::GetXYZ(double[3] point).

How do I call this function in Python, i.e. pass an array as argument? With no arguments, node.GetXYZ() gives TypeError: GetXYZ() takes exactly 1 argument (0 given).

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Dear @joachim

you have to first create a list array. For example.

# create annotation ROI MRML node 

roi = slicer.mrmlScene.AddNewNodeByClass("vtkMRMLAnnotationROINode")

# interact with it in the application.. move it around then to retrieve the center of the annotation ROI

point = [0., 0., 0.]
roi.GetXYZ(point)

HTH
Andinet

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Thank you, this was very helpful for me! It should be some tip for this on the wiki - how to emulate C++ calls through Python - because the C++ API is the only way I know how to do Python scripting.

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This page describes how to translate C++ API to Python: Slicer API — 3D Slicer documentation

Some additional useful tips: Python FAQ — 3D Slicer documentation

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