Defining parameters for Python Toolbox tool in ArcGIS Pro

Question

I have been posting similar questions recently, but I found a template code for a Python toolbox and I would like more help.

I am trying to create a tool in ArcGIS Pro that takes parameters from users (initially, the geodatabase filename) and shows the report on the screen.

I added to the template the function "getParameter." I thought this function will open up a dialog box for a user to choose a parameter, but it does not for some reason.

The following code has no syntax error. When I add a new Python toolbox and ran this code, it does run, but it says "no parameters," as the screenshot says. What change do I need to make?enter image description here

import arcpy
import os
class Toolbox(object):
 def __init__(self):
 """Define the toolbox (the name of the toolbox is the name of the
 .pyt file)."""
 self.label = "Toolbox"
 self.alias = ""
 # List of tool classes associated with this toolbox
 self.tools = [Report]
class Report(object):
 def __init__(self):
 """Define the tool (tool name is the name of the class)."""
 self.label = "Tool"
 self.description = ""
 self.canRunInBackground = False
 def getParameter(self): 
 arcpy.env.workspace = arcpy.GetParameterAsText(0)
 featureclasses = arcpy.ListFeatureClasses()
 for fc = in featureclasses:
 print (fc)
 def getParameterInfo(self):
 """Define parameter definitions"""
 params = None
 return params
 def isLicensed(self):
 """Set whether tool is licensed to execute."""
 return True
 def updateParameters(self, parameters):
 """Modify the values and properties of parameters before internal
 validation is performed. This method is called whenever a parameter
 has been changed."""
 return
 def updateMessages(self, parameters):
 """Modify the messages created by internal validation for each tool
 parameter. This method is called after internal validation."""
 return
 def execute(self, parameters, messages):
 """The source code of the tool."""
 return

• Kirk Kuykendall: Did you try returning something for getParameterInfo? pro.arcgis.com/en/pro-app/arcpy/geoprocessing_and_python/…
• Yoshi: So, are you saying that because in my code, it says params = None, it returns nothing? Should I change it to 0 then?
• Yoshi: The parameter need to be a path to a filename (initially, geodatabase filename.) What datatype should I choose for that?
• PolyGeo: You said that you "have been posting similar questions recently". Please always include links to any GIS SE questions that you mention in a new question so that potential answerers do not have to go looking for them before deciding whether this is actually a non-duplicate question.
• PolyGeo: Have you reviewed Defining parameters in a Python toolbox?

Answer 1

I suggest you look at the Python Toolbox documentation, particularly:

• Defining parameters in a Python toolbox
• Defining parameter data types in a Python toolbox
• Accessing parameters within a Python toolbox

Your code was not working because:

• your getParameterInfo method was returning None instead of a list of Parameter definitions
• Your getParameter method will never get called as it's not part of the python toolbox API
• Your execute method did nothing.

Here's a working example

import arcpy
class Toolbox(object):
 def __init__(self):
 """Define the toolbox (the name of the toolbox is the name of the
 .pyt file)."""
 self.label = "Toolbox"
 self.alias = ""
 # List of tool classes associated with this toolbox
 self.tools = [Report]
class Report(object):
 def __init__(self):
 """Define the tool (tool name is the name of the class)."""
 self.label = "Tool"
 self.description = ""
 self.canRunInBackground = True
 def getParameterInfo(self):
 # Define parameter definitions
 params = []
 # First parameter
 param0 = arcpy.Parameter(
 displayName="Input workspace",
 name="in_workspace",
 datatype="DEWorkspace",
 parameterType="Required",
 direction="Input")
 params.append(param0)
 return params
 def execute(self, parameters, messages):
 """The source code of the tool."""
 arcpy.env.workspace = parameters[0].valueAsText
 featureclasses = arcpy.ListFeatureClasses()
 for fc in featureclasses:
 messages.addMessage(fc)

• Yoshi: Thank you, but I just realized I have been barkin at the wrong tree. All this time I was thinking I was supposed to make Python toolbox, but actually I am supposed to make a script toolbox... Thank you tho!