FAQ:  Why am I getting an error accessing a multivalue parameter in Python at ArcGIS for Desktop 10.1?

【解决方案】
The data type for a multivalue parameter in a Python script changed in ArcGIS for Desktop 10.1.

In ArcGIS Desktop 10.0, a multivalue parameter (a collection of items) was a ValueTable object. The following is an example of accessing a multivalue table name parameter in ArcGIS Desktop 10.0:


============
import arcpy

tableList = arcpy.GetParameter (0) # a ValueTable object
rowCt = tableList.rowCount
arcpy.AddMessage ("rows: " + str(rowCt))

i = 0
while i < rowCt:
# Get table name from list
tbl = tableList.getValue (i, 0)
arcpy.AddMessage ("table name: " + tbl)
i += 1
============

In ArcGIS for Desktop 10.1 and later, running the above code returns the following syntax error:



rowCt = tableList.rowCount
AttributeError: 'list' object has no attribute 'rowCount'

The error occurs because the multivalue parameter is now a list object. An example of the updated code is as follows:


============
import arcpy

tableList = arcpy.GetParameter (0) # a List object
rowCt = len (tableList)
arcpy.AddMessage ("rows: " + str(rowCt))

i = 0
while i < rowCt:
# Get table name from list
tbl = tableList
arcpy.AddMessage ("table name: " + str(tbl))
i += 1
============


【创建及修改时间】
[i]Created: 6/9/2014

Last Modified: 6/30/2014
【原文链接】
http://support.esri.com/en/kno ... 42668