Nothing Happens When I run arcpy.management.AlterField()

[DarrenConly]

I'm trying to write a function that takes in a feature class and converts all its field names to uppercase, using the Alter Field tool. Here is my code:

def capitalize_fc_fnames(in_fc):
    # capitalizes all field names for specified feature class
    print("\nCapitalizing all field names for master network output feature class..")
    all_fields = [f.name for f in arcpy.ListFields(in_fc)]
    for f in all_fields:
        arcpy.management.AlterField(in_fc, f, new_field_name=f.upper())

I am running the function on a feature class in a file geodatabase. The function runs without errors, but when I open the feature class, none of the fields have been altered.

I have also tested in Pro using the Alter Field GUI tool on just one field, but with that nothing happens: no errors, no changes to the field names.

This post from 2017 suggests that at that time it was a known but unresolved bug that Alter Field did nothing. I *really* hope that's not still the case as I have 90+ fields I want to convert to uppercase. @BrandonFlessner did you ever find a solution to this? @DanPatterson do you have any sage input on this?

Thanks,

[DanPatterson]

syntax looks fine, but I would exclude fields that are not editable or required in your list comprehension

Field—ArcGIS Pro | Documentation

The only things that bug me right now are:

•  is the full path to the featureclass passed to the script?
• where are you running the function from (separate IDE, python IDE, notebook??)
• when you open the featureclass.... it won't update unless run from a script tool in arctoolbox or the python window.
• and.... is this a network dataset? (I think they have other constraints compared to "regular" featureclasses)

[DarrenConly]

Hi Dan,

•  is the full path to the featureclass passed to the script? Yes
• where are you running the function from (separate IDE, python IDE, notebook??) In a separate IDE in a python script, but I tested in Pro's python command prompt as well. Neither worked.
• when you open the featureclass.... it won't update unless run from a script tool in arctoolbox or the python window. I was running from the python command prompt in pro
• and.... is this a network dataset? (I think they have other constraints compared to "regular" featureclasses) No, just a line feature data set

@Anonymous User's answer seems to work (i.e., change to a different name, then change back to the capitalized version of the original name). But that's still not ideal because it moves the field name to the end.

[Anonymous User · Accepted solution]

I wonder if this is the extension of how it also has problems when trying to do it in catalog- it wont change cases if the names are the same. Just reverts back to whatever case it was... I'd try appending a temp value and then change it back to the desired name:

def capitalize_fc_fnames(in_fc):
    # capitalizes all field names for specified feature class
    print("\nCapitalizing all field names for master network output feature class..")
    all_fields = [f.name for f in arcpy.ListFields(in_fc)]
    for f in all_fields:
        arcpy.management.AlterField(in_fc, f, new_field_name=f'{f.upper()}_cmon')
        arcpy.management.AlterField(in_fc, f'{f.upper()}_cmon', new_field_name=f.upper())

[DarrenConly]

Hi Jeff,

This seems to work after testing out in the Pro python window. This approach also seems to move the field to the end, which is not ideal. I might end up using it if nothing else comes to mind.

[Anonymous User]

This might be a view/cache thing, or under the hood (more likely) it is creating a new field with the new name, and then doing a migrate from the old field so that would put them at the end.  If you could, can you create a new FC and field map the data to the uppercased fields? then save over the old?