How to interpret JsonDataObject data (e.g. from Statistics evaluator)

[bryn]

Recently I was trying to extract the average field value using the Sim4Life Python API. Since I found interpreting the JsonDataObject a bit difficult, I will share the code here. Hope it helps.

# -*- coding: utf-8 -*-
# This script was auto-generated by Sim4Life version 7.1.0.8835

import numpy
import s4l_v1.analysis as analysis
import s4l_v1.document as document
import s4l_v1.model as model
import s4l_v1.units as units
from s4l_v1 import ReleaseVersion
from s4l_v1 import Unit

try:
    # Define the version to use for default values
    ReleaseVersion.set_active(ReleaseVersion.version7_1)
    
    # Creating the analysis pipeline
    # Adding a new SimulationExtractor
    simulation = document.AllSimulations["EM"]
    simulation_extractor = simulation.Results()

    # Adding a new EmSensorExtractor
    em_sensor_extractor = simulation_extractor["Overall Field"]
    em_sensor_extractor.FrequencySettings.ExtractedFrequency = u"All"
    em_sensor_extractor.SurfaceCurrent.SurfaceResolution = 0.001, units.Meters
    document.AllAlgorithms.Add(em_sensor_extractor)

    # Adding a new StatisticsEvaluator
    inputs = [em_sensor_extractor.Outputs["SAR(x,y,z,f0)"]]
    statistics_evaluator = analysis.core.StatisticsEvaluator(inputs=inputs)
    statistics_evaluator.Mode = u"Value"
    statistics_evaluator.UpdateAttributes()
    document.AllAlgorithms.Add(statistics_evaluator)
    statistics_evaluator.Update()
    
    # Get JsonDataObject output and print the values
    stats = statistics_evaluator.Outputs[0].Data.DataSimpleDataCollection
    for k in stats.Keys():
        v = stats.FieldValue(k, 0)
        unit = stats.FieldUnit(k)
        name = stats.FieldDescription(k)
        print(f"{name} = {v} {unit}")

except Exception as exc:
    import traceback
    traceback.print_exc()
    # Reset active version to default
    ReleaseVersion.reset()
    raise(exc)

The output is: