Removing multiple fields in Arcpy with remove function

Question

I am trying to delete several fields within a feature class using the .remove function but receive the following error when just testing the remove function in the arcpy module;

ERROR 001334: Cannot delete required field Shape


import arcpy
fc="X:\GIS_PROJECTS\Documentation\Test\UA_GDB_1.gdb\Urban"
fields = arcpy.ListFields("X:\GIS_PROJECTS\Documentation\Test\UA_GDB_1.gdb\Urban")


for field in fields:
    print field.name

FCfields = [f.name for f in arcpy.ListFields(fc)]
DontDeleteFields = ['UA_ID', 'NAME', 'LSAD', 'LSAD_DESC', 'Join_Number', 'DensitySQMI', 'GeoID2', 'F15Growth','Shape', 'F14Growth', 'GrowthAvg', 'ConFinance500', 'ConFinance400', 'ConFinance300']
fields2Delete = list(set(FCfields) - set(DontDeleteFields))
arcpy.DeleteField_management(fc, fields2Delete)

Answer 1

What arcpy.ListFields returns is a python list. When you say list.remove(), you're asking for an item to be removed from the Python list. So for starters, if you want to delete a field from the FC, this won't do what you want. Second, the error you're getting states you can only remove 1 items at a time using the python list.remove() function. You've passed it a list of all your fields.

If you want to remove ALL fields in your FC, you can try the following:

fc = "c:/temp/path2/shp.shp"
for f in arcpy.ListFields(fc):
  if (f.type == 'OID' or f.type == 'Geometry'):
    print("cant delete {}".format(f.name))
  else:
    arcpy.DeleteField_management(fc, f.name)

Or, perhaps a slightly faster way, but requires you know the shape/oid field name:

fields = [f.name for f in arcpy.ListFields(fc)]
print(fields)
>>[u'ObjectID', u'Shape', u'City', u'Country', u'Name', u'Email', u'Manager']
fields.remove('Shape')
fields.remove('ObjectID')
arcpy.DeleteField_management(fc, fields)

One more code snippet - to get a list of all fields. Take a known list you have and remove those items from the field list and then do your delete with the subset list:

FCfields = [f.name for f in arcpy.ListFields(fc)]
DontDeleteFields = ['Shape_STArea__', 'Shape_STLength__', 'STATE', 'FIPS', 'Shape',  'Shape_Length', 'Shape_Area', 'AreaFT']
fields2Delete = list(set(FCfields) - set(DontDeleteFields))
arcpy.DeleteField_management(fc, fields2Delete)

Answer 2

I think the pythonic way of doing this should be as follows:

for f in arcpy.ListFields(fc):
    if f.name not in set(DontDeleteFields):
        try:
            arcpy.DeleteField_management(fc,f)
        except:
            print arcpy.GetMessages()

This will show an error message if it cannot delete the field but carries on processing. If there is no DontDeleteFields, then commenting out the if line will attempt deleting all fields.