Question : Python script error - Assertion error

Hello,
I am trying to use the code I got from here:

http://www.experts-exchange.com/Q_23068228.html

I have changed directory locations and the lines:

expTemplate = 'CON(ISNULL(%s), %s, %s * -1)'

to

expTemplate = '(%s, + (%s * 10))'

and

  numSuffix = LnumDir[-2:]   # last 2 chars
            idSuffix = LnumDir[-4:]    # last 4 chars

to

  numSuffix = LnumDir[-3:]   # last 3 chars
            idSuffix = LnumDir[-5:]    # last 5 chars

I get the following error:

C:\Documents and Settings\u4cncmgj>c:\python24\python "C:\Documents and Settings
\u4cncmgj\My Documents\code\to_create_redone_binLC16_with3digits.py
Traceback (most recent call last):
  File "C:\Documents and Settings\u4cncmgj\My Documents\code\to_create_redone_bi
nLC16_with3digits.py", line 51, in ?
    for landcover, donut, idSuffix in allLandcoverDonutAndIdSuffix(gisworkDir):
  File "C:\Documents and Settings\u4cncmgj\My Documents\code\to_create_redone_bi
nLC16_with3digits.py", line 40, in allLandcoverDonutAndIdSuffix
    assert os.path.isdir(DnumDir)
AssertionError

Here is the code I used:

# Multi_Output_Map_Algebra_sample.py
# Description:
#   Runs an expression built with the Map Algebra language.
# Requirements: None
 
import arcgisscripting
import glob
import os
 
gisworkDir = 'C:\GISWORK\Hibernacula\EUA_805\TOCREATE2016'
 
def log(s):
    f = open("C:/tester.txt","w")
    f.write(s)
    f.close()
 
 
def allLandcoverDonutAndIdSuffix(gisworkDir):
    '''Generates all tuples (landcover, donut, idSuffix) from the gisworkDir.'''
    ##log("1\n")
    # Prepare the path to the donuts.
    donutDir = os.path.join(gisworkDir, 'Donut')
    assert os.path.isdir(donutDir)
    ##log("2\n")
    # Iterate through sequence of top-level landcover subdirectories.
    mask = os.path.normpath(os.path.join(gisworkDir, 'landcover*'))
    ##log(mask)            
    for LDir in glob.glob(mask):      # full paths to LandcoverA, LandcoverB, etc.
        subdir = os.path.basename(LDir)
        ##log("3\n")
        # Iterate through all numbered landcover subdirs inside.
        mask2 = os.path.join(LDir, '*')
        for LnumDir in glob.glob(mask2):
            # Separate the counter part, the idSuffix and construct
            # the related donut numbered directory name.
            numSuffix = LnumDir[-3:]   # last 3 chars
            idSuffix = LnumDir[-5:]    # last 5 chars
            DnumDir = os.path.normpath(
                         os.path.join(donutDir, 'DONUT_' + numSuffix))
            assert os.path.isdir(DnumDir)  
            ##log("4")
            # Generate another output tuple.
            yield (LnumDir, DnumDir, idSuffix)
 
 
# Create the Geoprocessor object
gp = arcgisscripting.create()
expTemplate = '(%s, + (%s * 10))'
log("\n===== Output below: ====\n")
 
for landcover, donut, idSuffix in allLandcoverDonutAndIdSuffix(gisworkDir):
    # Construct the expression and the output directory name.
    outDir = os.path.join(gisworkDir, 'landcoverprep', 'Results', idSuffix)
    log("\n" + outDir)
    InExpression = expTemplate % (donut, landcover)
    log("  " + InExpression)
 
    # Check out Spatial Analyst extension license
    gp.CheckOutExtension("Spatial")
 
    # Process: MapAlgebra
    gp.SingleOutputMapAlgebra_sa(InExpression, outDir)
 
    log("Msg: " + gp.GetMessages())



Please advise,
Thanks,
MJ
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# Multi_Output_Map_Algebra_sample.py
# Description:
#   Runs an expression built with the Map Algebra language.
# Requirements: None
 
import arcgisscripting
import glob
import os
 
gisworkDir = 'c:\Giswork'
 
def log(s):
    f = open("C:/tester.txt","w")
    f.write(s)
    f.close()
 
 
def allLandcoverDonutAndIdSuffix(gisworkDir):
    '''Generates all tuples (landcover, donut, idSuffix) from the gisworkDir.'''
    ##log("1\n")
    # Prepare the path to the donuts.
    donutDir = os.path.join(gisworkDir, 'landcoverprep', 'Donut')
    assert os.path.isdir(donutDir)
    ##log("2\n")
    # Iterate through sequence of top-level landcover subdirectories.
    mask = os.path.normpath(os.path.join(gisworkDir, 'Landcoverprep\landcover*'))
    ##log(mask)             
    for LDir in glob.glob(mask):      # full paths to LandcoverA, LandcoverB, etc.
        subdir = os.path.basename(LDir)
        ##log("3\n")
        # Iterate through all numbered landcover subdirs inside.
        mask2 = os.path.join(LDir, '*')
        for LnumDir in glob.glob(mask2):
            # Separate the counter part, the idSuffix and construct 
            # the related donut numbered directory name.
            numSuffix = LnumDir[-2:]   # last 2 chars
            idSuffix = LnumDir[-4:]    # last 4 chars
            DnumDir = os.path.normpath(
                         os.path.join(donutDir, 'DONUT_' + numSuffix))
            assert os.path.isdir(DnumDir)  
            ##log("4")
            # Generate another output tuple.
            yield (LnumDir, DnumDir, idSuffix)
 
 
# Create the Geoprocessor object
gp = arcgisscripting.create()
expTemplate = 'CON(ISNULL(%s), %s, %s * -1)'
log("\n===== Output below: ====\n")
 
for landcover, donut, idSuffix in allLandcoverDonutAndIdSuffix(gisworkDir):
    # Construct the expression and the output directory name.
    outDir = os.path.join(gisworkDir, 'landcoverprep', 'Results', idSuffix)
    log("\n" + outDir)
    InExpression = expTemplate % (donut, landcover, landcover)
    log("  " + InExpression)
 
    # Check out Spatial Analyst extension license
    gp.CheckOutExtension("Spatial")
 
    # Process: MapAlgebra
    gp.SingleOutputMapAlgebra_sa(InExpression, outDir)
 
    log("Msg: " + gp.GetMessages())
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Answer : Python script error - Assertion error

Replace that assert (at line 40) with
if not os.path.isdir(DnumDir): continue
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