I'm writing a script that will create a list of values from the field "Year_" using search cursor, and then a set() of unique values from the list. I then want to iterate through the set making a main folder with the current iteration value for "Year_" followed by the creation of a selection variable also based on the value of the current iteration. From this selection I want a second list made based on the values in the "Customer" field and then a set of unique values from the list. Finally, the script should make sub folders of unique customer names based on the unique values in the set:

    # Import modules

    import arcpy, os , sys, string

    # Create environmental variables

    arcpy.env.overwriteOutput = True
    arcpy.env.workspace = r"C:\data.gdb"

    # Set variables

    input = r"C:\data.gdb\layer"
    yearField = "Year_"
    custField = "Customer_Name"
    rootpath1 = r"S:\Shared\Orders"

    # Use Search Cursor to make list of years and then make set of years with unique values
     yearList = [row[0] for row in arcpy.da.SearchCursor(input,(yearField))]
     yearSet = set(yearList)

     #Make main year directories
     for year in yearSet:
         rootpath2 = os.mkdir(os.path.join(rootpath1,year) #establishes root  path for subfolders while making main directories
         selection = arcpy.SelectLayerByAttribute_management(input,year)#creates variable based on current selected year in input layer
        for customer in selection:
            customerList = [row[0] for row in arcpy.da.SearchCursor(input,(custField))] #Use Search Cursor to make list of customers and then make set of   customers with unique values
            customerSet = set(customerList)
            for name in customerSet:
                os.mkdir(os.path.join(rootpath2,name) #makes unique customer sub folders

So if the values for years are 2010, 2010, 2011, 2012, 2013, 2013 in the field "Year_" a list will be made and the resulting set would be [2010,2011,2012,2013]. The first iteration would find 2010 and make the pathway r"S:\Shared\Orders\2010".

While in this iteration, 2010 would be used to select by attributes. If customers Joe, Joe, Ann, Bob, Mary, Mary, Mary were found a list would be made and then the set [Joe, Ann, Bob, Mary]. Finally a for loop will iterate through the set and make the pathways:

r"S:\Shared\Orders\2010\Joe" r"S:\Shared\Orders\2010\Ann" r"S:\Shared\Orders\2010\Bob" r"S:\Shared\Orders\2010\Mary" However, I get a an error "Failed to run script - syntax error - invalid syntax at the line where I make the selection variable.

  • 3
    Do you have a typo in your post or in the script? (the nested for isn't aligned correctly)
    – Vince
    Sep 18, 2015 at 1:11
  • No. It's nested correctly in PythonWin. Just missed a space when formatting it as code for the post.
    – geoJshaun
    Sep 18, 2015 at 1:50

1 Answer 1


I think the error that you are seeing is due to a missing space before the #:

Instead of:

selection = arcpy.SelectLayerByAttribute_management(input,year)#creates variable based on 


selection = arcpy.SelectLayerByAttribute_management(input,year) #creates variable based on 

However, I think this will just move the error because I don't think the result object returned by arcpy.SelectLayerByAttribute_management() will be iterable in the way that you are trying.

I would make the selection using:


and then use a Search Cursor on the layer instead.

  • I left out the outer parentheses in os.mkdir(). Corrected it and now I am getting this error:TypeError: 'NoneType' object has no attribute 'getitem'
    – geoJshaun
    Sep 18, 2015 at 15:01
  • Okay. So I should make a layer from the selection and then use search cursor. I misread your post.
    – geoJshaun
    Sep 18, 2015 at 21:06

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