I tried, but it doesn't works. I tried similar version, none works.
import arcpy
...
... # Local variables:
... arcpy.env.workspace = r'C:\Teste_Auto_CLEIA\Auto_Classi\Dinamica_GDB.gdb'
...
... #List FC # line 6
... FC = arcpy.ListFeatureClasses("S_pol_Din*")
... Feature = FC[0]
... print"Feature: "+str(Feature)
...
... #List AnotherFC # line 11
... FCName = arcpy.ListFeatureClasses("pol*")
... FC_Name = FCName[1]
... print"FC_Name: "+str(FC_Name)
... FCNameCut = FC_Name[19:36] # Isn't original lane
... print"FCNameCut "+FCNameCut
...
... #Calculate field (D2clust200m) #Line 18
... print("FCNameCut is: {}".format(FCNameCut))
... if FCNameCut is not None:
... expr = FC_Name.replace(str(FCNameCut), "test") #I tried with FCNameCut and not with FC_Name too
... arcpy.CalculateField_management (Feature, "D2clust200m", expr,"PYTHON_9.3")
... print"Done"
...
Feature: S_pol_Din_DepL82270692015146eAnt015130
FC_Name: pol_Din_DepL82270692015178eAnt015146
FCNameCut 2015178eAnt015146
FCNameCut is: 2015178eAnt015146
Runtime error Traceback (most recent call last): File "<string>", line 22, in <module> File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\management.py", line 3129, in CalculateField raise e ExecuteError: ERROR 000539: Error running expression: pol_Din_DepL8227069test Traceback (most recent call last): File "<expression>", line 1, in <module> NameError: name 'pol_Din_DepL8227069test' is not defined Failed to execute (CalculateField).