my code fails with "geoprocessing object not iterable" in 9.3 but works in 10

[kyleturner]

Can anyone explain why my code fails with "geoprocessing object not iterable" in 9.3 but works in 10. Are there some compatibility issues going on? I wrote the python code in 10 but made sure not to make any calls to arcpy.
I invoked, gp = arcgisscripting.create(9.3)

My understanding is before 9.3, python didn't use 'real' lists, so calling list methods would obviously fail. Is that wrong? Is 9.3 not able to use list methods?

The following code, I believe, is where the problem is...I think??

# function to return appropriate 3.0 feature class for given 2.6 feature class # and it returns the name of the fieldname, FC_26_name def which30(two6ftrcls):      two6FC = two6ftrcls     whereclause = "Two6FCs = '" + two6FC + "'"     gp.AddMessage("whereclause is " +whereclause)     crosswalk = ShellPath + "/Two630FC_IDPKxwalk.dbf"     # The variables row and rows are initially set to None, so that they     #  can be deleted in the finally block regardless of where (or if)     #  script fails.     row, rows = None, None     Three0ftrlst = []     FC_26namelst = []     rows = gp.SearchCursor(crosswalk,whereclause)     row = rows.next()     if (row == None):         gp.AddMessage("check the Two630FC_IDPKxwalk.dbf table for Two6FCs -->" +two6FC)     elif (row != None):        rows = gp.SearchCursor(crosswalk,whereclause)        for row in rows:            if not row.isNull("Three0FCs"):               Three0ftr=row.getValue("Three0FCs")               Three0ftrlst.append(str(Three0ftr))               FC_26name = row.getValue("FC_26")               FC_26namelst.append(str(FC_26name))      if row: del row     if rows: del rows      return Three0ftrlst, FC_26namelst

[markdenil · Accepted solution]

The difference is in the 9.3 and 10 cursor objects.
The difference manifests itself in the application version, not in the geoprocessor version
(that is, a 9.3 geoprocessor cursor created in 10 uses the 10 behavior,
while the same code (with a 9.3 geoprocessor cursor) that will run in 10 will not run in 9.3)
(...and vice-versa)

In 10, one iterates the cursor:

for theRow in theCursor:     pass

in 9, one steps the cursor manually because the cursor cannot be iterated:

theRow = theCursor.next() while theRow:     pass     theRow = theCursor.next()

Even in 10, one manually steps an InsertCursor (for obvious reasons)

This is a real pain when having to write code that works in both versions
(don't ask, but I hope to be clear of 9.3 soon)

Actually, I rather liked the 9.3 behavior. One could easily run multiple simultaneous cursors in parallel.
Yes, there are other ways to do it, but I liked having the option.

[kyleturner]

Mark,

Wow...I'm glad I got someone with your knowledge to respond.
So, how do I write it to be used in both versions.

Incidentally, the only reason my code calls rows.next() is because early on in the development I was checking if rows was == None, which it never is because it always returns an object. So, I had to advance to a row to see if the row was == None.
Do you follow? (Also, have you figured out that I barely know what I'm doing....probably.)

Again, any help is greatly appreciated.
Feel free to email me at: turnerkyle@hotmail.com