Execute 'Iterate Feature Selection' in ModelBuilder only if Features are Selected

Question

I have a feature layer, and with ModelBuilder (ArcMap 10.8) I'm trying to ensure that the "Iterate Feature Selection" tool is carried out only if there are selected features; if no feature are selected the tool and next steps shoul be skipped. Following the instruction from the Online Help on Using If-Then-Else logic for branching I create a simple python script with two ouputs. If the output indicating that features are selected is true the process should run.

import arcpy
layerName = arcpy.GetParameterAsText(0)
desc = arcpy.Describe(layerName)
if not desc.FIDSet == '':
 arcpy.SetParameterAsText(1,"true")
 arcpy.SetParameterAsText(2,"false")
else:
 arcpy.SetParameterAsText(1,"false")
 arcpy.SetParameterAsText(2,"true")

The issue is when no feature are selected the process still run for every feature in the layer.

Example of model builder with two output options Even when I use 'Iterate Feature Selection' in a separate model, all steps are executed, even if no features are selected

Example of separate model builder for the iteration

How can I resolve?

• JasonInVegas: It looks like you are inputting and/or storing three parameters (0, 1, 2) in the first block, but as the selected answer below comments, you haven't chosen to show what you do with them once loaded.

Answer 1

It's not possible to answer your question as you do not show how you pass in the parameters into your script tool. I suspect the issue is there.

Below is an easier solution using the calculate value tool.

Model

The Calculate value tool is set up as below:

Calculate value tool

For your convenience here is the Code Block:

import arcpy
def hasSelection(layer):
 desc = arcpy.Describe(layer)
 if desc.FIDSet == '':
 b = False
 else:
 b = True
 return b