AddError

Summary

Adds a custom error message (severity of 2) to the messages of a script tool or Python toolbox tool.

When a tool is run, arcpy is fully aware of the application it is called from. One major effect of this is that you can write messages in Python and your messages automatically appear on the tool dialog box, in the history, and the Python window.

Syntax

AddError (message)

Parameter	Explanation	Data Type
message	The error message to add.	String

Code sample

AddError example

Add a custom geoprocessing error message.

import arcpy

fc = arcpy.GetParameterAsText(0)

# Get the count from GetCount's Result object
feature_count = int(arcpy.GetCount_management(fc).getOutput(0))

if feature_count == 0:
    arcpy.AddError("{0} has no features.".format(fc))
else:
    arcpy.AddMessage("{0} has {1} features.".format(fc, feature_count))