Sure, unfortunalty, you can't just change a field, so basically, it creates a field map, modifies it, then replaces the existing fields with the new "mapped" fields.This one is set to work within all DS's within a FGDB, could easily be modified to only work on one FC, etc.
import arcpy, os
ws = r'D:\update\wch_updated.gdb'
arcpy.env.workspace = ws
datasets = arcpy.ListDatasets()
excludeList = ['Base','OSEGrids','River_Flows','Utilities','Wells','MR']
# Overwrite pre-existing files
arcpy.env.overwriteOutput = True
datasets.append("") # this appends a blank onto the dataset list so it picks up FC's in the base FGDB level.
for ds in datasets:
if ds not in excludeList: # only do this to DS's not in my exclude list
print "working on ",ds
fcs = arcpy.ListFeatureClasses("","",ds)
for fc in fcs:
print "creating field maps"
fieldmappings = arcpy.FieldMappings()
fieldmappings.addTable(fc)
for field in arcpy.ListFields(fc, "", "String"):
#Find all fields other than type of ObjectId and Geometry
# if (field.type != 'OID') & (field.type != 'Geometry'): # I commented this as my ListFields limits to "String" fields only
#Create a new Field Map Object and populate it
print "populating object for ",fc
fldmap_Changed = arcpy.FieldMap()
fieldName = field.name
fldmap_Changed.addInputField(fc, fieldName)
#Get a new field object from the Field Map Object and set the Allow Null Property to False
print "setting to false"
fld_Changed = fldmap_Changed.outputField
fld_Changed.isNullable = False
#Add the field back to the Field Map Object
fldmap_Changed.outputField = fld_Changed
#Find and replace the current field map in the Field Mappings with the new Field Map Object
print "replacing current field map"
index = fieldmappings.findFieldMapIndex(fieldName)
fieldmappings.replaceFieldMap(index, fldmap_Changed)
del fldmap_Changed, fld_Changed
print "outputting fc ",fc
arcpy.FeatureClassToFeatureClass_conversion(ds + os.sep + fc, arcpy.env.workspace, ds + os.sep + fc + "Copy1", "", fieldmappings)
####
### The script makes a copy in each dataset of the original.
### This section removes the original and renames the copy to the original name
####
for fc in fcs:
if arcpy.Exists(ds + os.sep + fc):
print "deleting ",ds + os.sep + fc
arcpy.Delete_management(ds + os.sep + fc)
print "creating ",fc,"from ",ds + os.sep + fc + "Copy1"
arcpy.FeatureClassToFeatureClass_conversion(ds + os.sep + fc + "Copy1", arcpy.env.workspace, ds + os.sep + fc, "")
arcpy.Delete_management(ds + os.sep + fc + "Copy1")
del fieldmappings
arcpy.Compact_management(ws) # compact FGDB to removed locks and optimize performance
R_
