Updates the values for a unique symbology renderer based on range domain values.

updateSymbologyBasedOnDomain.py

#
# @date 27/05/2015
# @author Cindy Williams
#
# Updates the values for a unique symbology renderer 
# based on range domain values. The layer must have
# the unique symbols renderer enabled manually.
#
# For use in the Python window in ArcMap.
#

import arcpy

mxd = arcpy.mapping.MapDocument("CURRENT")
lyr = arcpy.mapping.ListLayers(mxd)[4] # 5th layer in TOC
rvd_name = "rvd_1_12" # Name of range value domain
rvd_values = []

# Courtesy of pythoncentral.io - works like range(), but for floats
# The range domain type is Short, but the min and max are stored as floats
def frange(start, stop, step):
    i = start
    while i < stop:
        yield i
        i += step

# Check if the layer has the unique symbology renderer
if lyr.symbologyType == 'UNIQUE_VALUES':
	# Access domains in the workspace using ListDomains		
	for domain in arcpy.da.ListDomains(lyr.workspacePath):
		# Check for name
		if domain.name == rvd_name:
			for n in frange(dom.range[0], dom.range[1] + 1, 1):
				# Can't append directly into classValues
				rvd_values.append(int(n))
	lyr.symbology.classValues = rvd_values # Set unique value list
	
arcpy.RefreshTOC()
mxd.save()