What is the benefit of the arcpy GetParameterAsText function?

I know that its purpose is to return parameters as text but what is the real benefit?

  • Python string functions are impressive, i.e. you can easily split inputs inside script for multivalue parameters. Also no need to bother with os separator when parameter is folder, database etc. – FelixIP Nov 22 '19 at 4:58

The summary on the Esri GetParameterAsText documentation states:

Gets the specified parameter as a text string by its index position from the list of parameters.

Functionally this allows you to pass arguments to a Python script tool. Script tools allow you to provide custom functionality in a GUI to those who do not want to use Python.

The documentation also provides an example of the usage:

import os
import arcpy

# Set the input workspace, get the feature class name to copy
#  and the output location.
arcpy.env.workspace = arcpy.GetParameterAsText(0)
in_featureclass = arcpy.GetParameterAsText(1)
out_workspace = arcpy.GetParameterAsText(2)

out_featureclass = os.path.join(out_workspace,

# Copy feature class to output location
arcpy.CopyFeatures_management(in_featureclass, out_featureclass)
  • so in this example the tool dialog box would have those three parameters that are prompting the user to input? Also, is the os.path.join trying to join different workspaces? – ryanmagowan Nov 22 '19 at 4:54
  • Yes, the script tool dialogue box would have those three parameters which the user can input in the script tool. os.path.join() is combining the workspace path (e.g. /path/to/your/geodatabase.gdb) and the basename (e.g. some_name) to produce /path/to/your/geodatabase.gdb/some_name – Aaron Nov 22 '19 at 4:58

In the ArcGIS Pro Help for arcpy.GetParameterAsText() its Summary is that it:

Gets the specified parameter as a text string by its index position from the list of parameters.

The way I think of it is that it is the means used to communicate, as text rather than objects, the choices made by an end user from the tool dialog that fronts a Python Script Tool of ArcPy.

The first parameter that the tool's author configures on its tool dialog is referenced from the script by using an index of 0 i.e. arcpy.GetParameterAsText(0).

There is an alternative way to reference the first parameter on the tool dialog, and that is as sys.argv[1] but that has limitations in the number of characters that it can accept whereas arcpy.GetParameterAsText() has no character limit. The two alternatives are documented in Accessing parameters in a script tool.

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