I am trying to add a field in a feature class that is populated with the number (or count) of how many other features in that same feature class have the same attribute value in a particular field. For example, I have a feature class of gas wells that has an attribute field with the wells pad name called "PadName". I want to create a field in this same feature class with the total count of how many wells share that same "PadName".

I am able to get the count of how many features share that same pad name but I am struggling to populate the newly create "COUNT" field with that number?

Below is my current code.

import arcpy, os, sys

fc = r"GIS\mygeodatabase.gdb\wells"
field = "PadName"
count = "COUNT"

    arcpy.AddField_management(fc, "COUNT", "TEXT", "", "", "10", "", "NULLABLE", "NON_REQUIRED", "")
    print "Successfully Created Count Field!"
    print "Failed to Create Count Field"

Occurances = []
with arcpy.da.SearchCursor (fc, field) as cursor:
    for row in cursor:
        Occurances.append (row[0])

for i in set(Occurances):
    icount = Occurances.count(i)
    print str(i) + ":", icount, "features"
    with arcpy.da.UpdateCursor(fc,count) as cursor:
        for row in cursor:
            row[0] = Occurances.count(i)

It is populating my new "COUNT" field that I created but it is giving every feature a value of "5" for some reason?

1 Answer 1


First count the instances of each value in a dictionary in the format {"value": count} using a Search Cursor, then in an Update Cursor check what the value is, then write the count to the new field.

occurrences = dict() # Create a dictionary to count the values
with arcpy.da.SearchCursor(fc, field) as cursor:
    for row in cursor:
        # Count the number of times each value occurs in the field
        occurrences[row[0]] = occurrences.get(row[0], 0) + 1

with arcpy.da.UpdateCursor(fc, [field, count]) as cursor:
    for row in cursor:
        row[1] = occurrences[row[0]]

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