Export Table of Unique Values by Field

Question

I get a lot of shapefiles with no metadata. Often there are tons of table columns (fields) with no description of what the column is for or what the coded values mean.

Is there an easy way to export a table so that the domain of unique values are listed per column?

In other words, if a table has two columns, say, Color and Shape, is there a way to export a table that lists all the unique values in Color and all the unique values in Shape?

I know a quick way is to open "Select by Attribute" in ArcMap, select a field and click "Get Unique Values" to see the list of unique attributes within the field. It would be great if there was an easy way to export a table of these unique values by column (field).

To keep it simple, I'm just interested in text or string fields.

Answer 1

Delete Identical tool will do this for you. Here's the documentation for Desktop and Pro version. Caution: This tool modifies the input data! Make a copy of your dataset before applying this.

Answer 2

Taking Vince's comment and turning it into code, the following should work in the interactive Python Window in Pro or the Pro Python Command Prompt:

import arcpy
from collections import defaultdict
from pprint import pprint

tbl = # path to table or feature class or name of table view of feature layer

desc = arcpy.Describe(tbl)
field_names = [field.name 
               for field 
               in desc.fields 
               if field.type not in ('OID', 'GlobalID', 'Geometry')]

unique_values = defaultdict(set)
with arcpy.da.SearchCursor(tbl, field_names) as cur:
    for row in cur:
        for i, value in enumerate(row):
            unique_values[field_names[i]].add(value)
            

pprint(unique_values)

Answer 3

The only solution is Python with mighty Pandas:

import pandas as pd
import os, simpledbf
from simpledbf import Dbf5

allFields=pd.DataFrame(columns = ["FOLDER","FILE","FIELD","VALUE"])
# traverse root directory, and list directories as dirs and files as files
i=0
for root, dirs, files in os.walk("C:/scratch/backup"):
    path = root.split(os.sep)
    for file in files:
        if file[-4:]!=".dbf":continue
##        print root, file
        dbf = Dbf5(root+os.sep+file)
        df = dbf.to_dataframe()
        for field in list(df):
            fieldType = df[field].dtypes
            if fieldType!='object':continue
            print field
            for item in df[field].unique():
                allFields.loc[i]=[root,file,field,item]
                i+=1
allFields.to_csv (r'c:\SCRATCH\output.csv', index = None, header=True)

I tested it on folder with few shapefiles, might take a long time in your case. Use filters on output.csv in Excel:

Note you'll need to install simpledbf. My bad, more than 5 lines, learning curve.