Update only blank, null field attributes

Question

I need to only update the fields attributes that are blank or Null, there are some attributes in Feilda and I want to skip those but I am not sure how do to do that. I have the following.

with arcpy.da.UpdateCursor(fc,['Fielda','COUNT','Field1']) as cursor:
    for row in cursor:
         if row[0] not in (None, "", " "):
            row[2] = ",".join(dict1[row[0]])
            cursor.updateRow(row)

2Quiker · Answer

I meant that I need to update Field1 and that Field1 has some attributes and also FieldA sometimes has attributes.

dict1 = dict()
with arcpy.da.SearchCursor(fc,['FieldA','COUNT','FieldB']) as cursor:
    for row in cursor:
        if row[0] not in (None, "", " "):
            dict1.setdefault(row[0],[]).append(str(row[2]))

with arcpy.da.UpdateCursor(fc,['FieldA','COUNT','Field1']) as cursor:
    for row in cursor:
         if row[2] is None:
            if row[0] not in (None, "", " "):
                row[2] = ",".join(dict1[row[0]])
                cursor.updateRow(row)

Anonymous User · Answer

Your conditional as written is testing if the Fielda is not null so its doing the opposite of what you are wanting to do.

just change your conditional:

if row[0] in [None, "", " "]:

or you can filter nulls in the where clause:

with arcpy.da.UpdateCursor(fc, ['Fielda', 'Field1'], 'Fielda IS NULL') as cursor:
   for row in cursor:
      row[1] = ",".join(dict1[row[0]])
      ...

DominicRobergeIADOT · Answer

still don't know where your dict1 is defined but this code will skip the rows with records

with arcpy.da.UpdateCursor(fc,['Fielda','COUNT','Field1']) as cursor:
    for row in cursor:
         if row[0] not in (None, "", " "):
            row[2] = ",".join(dict1[row[0]])
            cursor.updateRow(row)             
         else:
             print("All good, nothing to do here")