How to use a feature set as an output parameter in a Python Toolbox?

Question

I'm having trouble setting a "Feature Set" output parameter from a .pyt .. I'm using ArcGIS 10.1 SP1.

Here’s a short script that can be invoked either from a classic toolbox (thru the main() function; one setup with same parameters here), or as a .pyt .. it works as expected when invoked from a classic toolbox, but does not as a .pyt:

import arcpy
class Toolbox(object):
 def __init__(self):
 self.label = "FeatureSet Output Test"
 self.alias = ""
 self.tools = [Test]
class Test(object):
 def __init__(self):
 self.label = "Test1"
 self.description = "Output a few points in a feature set"
 self.canRunInBackground = False
 def getParameterInfo(self):
 params = []
 param0 = arcpy.Parameter(
 displayName = "FS Output", name = "fsOutput",
 datatype = "Feature Set", parameterType = "Derived", direction = "Output")
 params.append(param0)
 param1 = arcpy.Parameter(
 displayName = "JSON Output", name = "strOutput",
 datatype = "String", parameterType = "Derived", direction = "Output")
 params.append(param1)
 return params
 def execute(self, parameters, messages):
 gdbPath = ‘in_memory’
 featureClassName = ‘points’
 featureClass = ‘{}/{}’.format(gdbPath, featureClassName)
 try:
 arcpy.AddMessage(‘Creating a point feature class with 1 text attribute’)
 if arcpy.Exists(featureClass):
 arcpy.Delete_management(featureClass)
 arcpy.CreateFeatureclass_management(
 out_path=gdbPath, out_name=featureClassName, geometry_type=’POINT’,
 spatial_reference=arcpy.SpatialReference(4326))
 arcpy.AddField_management(
 in_table=featureClass,
 field_name=’Attribute1’, field_type=’TEXT’)
 arcpy.AddMessage(‘Inserting a couple points’)
 with arcpy.da.InsertCursor(featureClass, (‘SHAPE@XY’, ‘Attribute1’)) as cur:
 cur.insertRow(((1, 1), ‘point at 1, 1’))
 cur.insertRow(((2, 2), ‘point at 2, 2’))
 arcpy.AddMessage(‘Setting the output parameters’)
 featureSet = arcpy.FeatureSet(featureClass)
 # Has no effect in either .tbx or .pyt case .. no error, just does nothing.
 parameters[0].value = featureSet
 # Does what's expected for classic .tbx; does nothing
 # for .pyt .. again, no error, just does nothing.
 # You can comment this line out for testing the first set method ..
 arcpy.SetParameter(0, featureSet)
 # This works fine in both .tbx and .pyt
 parameters[1].value = featureSet.JSON
 except Exception as e:
 arcpy.AddError(str(e))
def main():
 tool = Test()
 tool.execute(arcpy.GetParameterInfo(), None)
if __name__ == ‘__main__’:
 main()

Not sure what I'm doing wrong .. Any suggestions?

• PolyGeo: I've only ever used feature sets for input and thought that, rather than output, was what they were designed for. It will be a while before I can look at this so I'm going to include links to your posting on the ArcGIS Discussion Forum and the Help Page to assist later.
• cwa: I got a similar answer in post you linked to; using "datatype = 'Feature Class'" instead of "datatype = 'Feature Set'" does fix my problem. If you can offer any insight into what the real difference between a 'Feature Set' vs 'Feature Class' is, I'll gladly accept your answer.

Answer 1

I've only ever used Feature Sets for input and thought that, rather than output, was what they were designed for.

My understanding of Feature Sets comes from here .

From what I can tell they are simplified Feature Classes but simplified in what ways I do not know.