Cross-posted from GIS Stack Exchange. I have created a few different ArcGIS Python Toolboxes, but one thing I can't quite understand is when to apply "schema.clone = True" to a parameter. All of the examples I have seen show that I should be using it for derived parameters, as shown below, taken from Parameter Dependencies.
param0 = arcpy.Parameter(
displayName="Input Features",
name="in_features",
datatype="GPFeatureLayer",
parameterType="Required",
direction="Input")
param2 = arcpy.Parameter(
displayName="Output Features",
name="out_features",
datatype="GPFeatureLayer",
parameterType="Derived",
direction="Output")
param2.parameterDependencies = [param0.name]
param2.schema.clone = True
However, when I try that on my code, it says the Tool is invalid when looking at it in Catalog. It gives me the following error when I click on the "Why..." button.
Traceback (most recent call last):
File "<string>", line 481, in getParameterInfo
AttributeError: 'NoneType' object has no attribute 'clone'
Here is what my code looks like. It works perfectly when I remove the schema clone line, which is confusing me. What exactly does that line do for me and when do I need it if it works fine without it?
input_table = arcpy.Parameter(
displayName="Table or Feature Class",
name="input_table",
datatype=["GPFeatureLayer", "GPTableView"],
parameterType="Required",
direction="Input")
params.append(input_table)
output_table = arcpy.Parameter(
displayName="Derived Output Table or Feature Class",
name="output_table",
datatype=["GPFeatureLayer", "GPTableView"],
parameterType="Derived",
direction="Output")
output_table.parameterDependencies = [input_table.name]
output_table.schema.clone = True
params.append(output_table)
I am currently running version 10.4
Someone over at GIS SE did some testing and led me to the following conclusions:
- When I changed all the data types to ["GPFeatureLayer", "GPTableView"] it gave me the error.
- I then changed all the data types to ["GPFeatureLayer"], and it still gave me the error.
- Finally, I changed all the data types to "GPFeatureLayer", and it opened fine again.
This tells me you can only have 1 data type, and it cannot be in brackets.
So, how do you handle cases where you need multiple possible input types? That seems like a pretty common use case. Or do you simply not need to include the schema clone line at all?
