I have a File GDB that has domains and coded values. I would like to extract those values from the GDB and build a dictionary. For example:

I have hundreds of domains and with each domain has a set of coded values associated with it.

*Domain* , *Coded Value*
['tree', 'pine']
['tree', 'magnolia']
['tree', 'fir']
['tree', 'grey pine']
['tree', 'oak']
['soil', 'clay']
['soil', 'loam']
['soil', 'sandy']
['brush', 'manz']
['brush', 'short']
['water', 'wetland']
['water', 'lake']

I want this:

{'tree': ['pine', 'magnolia', 'fir', 'grey pine']}
{'soil': ['clay', 'loam', 'sandy']}
{'brush': ['manz', 'short']}
{'water': ['wetland', 'lake']}

How do i accomplish this by using arcpy.da.ListDomains? This is what I have so far:

import arcpy

doms = arcpy.da.ListDomains(gdb)

    for dom in doms:

    if dom.domainType == 'CodedValue':
        codedvalues = dom.codedValues
        for code1 in codedvalues:

             list1 = []

             c_data = "{},{}".format(dom.name, code1)
             domain2 = c_data.split(",")[0]
             code2 = c_data.split(",")[1]

             list1 = [domain2, code2]
             print list1  #this prints out the first code block shown above
  • 1
    {'tree': 'pine', 'magnolia', 'fir', 'grey pine'} isn't a dictionary. A dictionary is {Key: Value}, so you'd probably need a list to record the values e.g. {'tree': ['pine', 'magnolia', 'fir', 'grey pine']} to make it how you're suggesting
    – Midavalo
    Commented Jun 9, 2016 at 23:31
  • Yes I need: {'tree': ['pine', 'magnolia', 'fir', 'grey pine']}
    – Djb
    Commented Jun 9, 2016 at 23:46
  • To append values into your empty list you could use .append() on it.
    – PolyGeo
    Commented Jun 10, 2016 at 0:14

1 Answer 1


The following should do the job:

codedDomains = {domain.name: domain.codedValues.keys() for domain in arcpy.da.ListDomains(gdb) if domain.domainType == 'CodedValue'}

Basically, it uses a list comprehension to populate a dictionary, but only if it is a coded value domain. If you wanted to have it populated with the description instead of the coded value, replace the




This entry in the ArcGIS help may also give other options on domain objects that might be helpful.

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