I am trying to identify and flag exact duplicate attribute labels (text) in a field. I can't access "Delete Identical" with my Standard ArcGIS license.

I have ET Geowizards installed, they have a tool that removed duplicates with exact the same shape. tried to run it and then select by location between the output and the input, but it doesn't work properly.

I don't have an FME license and need to do this with ArcGIS Desktop.


5 Answers 5


Instructions provided demonstrate how to use the Field Calculator to identify duplicate field values. Single occurrences and the first occurrence of multiple values are flagged with 0. Duplicates are flagged with 1.

Create a new field. Set the type as short or long integer and accept the other defaults. Right-click the newly created field and select Field Calculator. Select the Python parser. Ensure that the 'Show Codeblock' option is checked. Paste the following code into the Pre-Logic Script Code box:

uniqueList = []
def isDuplicate(inValue):
  if inValue in uniqueList:
    return 1
    return 0

Type 'isDuplicate(!Field!)' in the lower expression box and replace the word 'Field' with the name of the field that contains the duplicated values. Click OK. All duplicate records are designated with a value of 1 and non-duplicate records are designated with a value of 0 in the new field.

from: http://support.esri.com/cN/knowledgebase/techarticles/detail/38700

  • 2
    This will find duplicate values, but will not mark all values that exist more than once. This will mark the first duplicate as a duplicate - but it will not mark the originating value as having a duplicate - so use with caution. If you want to truly know all fields that have values that exist more than once in a table, use the "Summarize" tool.
    – Malcolm
    May 15, 2020 at 17:18

If you cannot create a new column or data is read only then there is a good answer given at esri site.

Open Select by attributes and in Where section type


Replace FIELD_NAME and TABLE_NAME as necessary.

  • Note: per the linked documentation "The procedure outlined is not available for data stored in file geodatabase or shapefile formats."
    – SMiller
    Dec 5, 2018 at 16:58

Concatenate... 1. Create a new column and concatenate all previous columns. Apply "summarize" and values greater than 1 are duplicates, to place them on the table or map you must use "relate" between the two tables (sum_output and the original table) using the concatenated field in common. For example, for a layer of points, lines or polygons spatially identical (same coordinate), you must create and calculate the geometry fields (X, Y, Start, End, centroid, etc.) and concatenate too. It's manual, but it has worked.

Sheet Excel... 2. Another way: is to create the geometry columns and copy the entire table to Excel and then apply the formula "concatenate" to locate duplicate items (clean the sheet and loads in ArcMap, apply "relate" tables using "Objectid" column by removing in "Start editing" do not need it...


I've been often needing to find and select duplicate attributes so I made an addin for that. It runs slow on a large number of records and is sort of experimetal at the moment but give it a try: http://newgold.maps.arcgis.com/home/item.html?id=e2834a70b67b48fc99be86630d056dea

Only works with File and Personal Geodatabase feature classes. Works with the entire dataset or within a selection. Allows you to ignore Nulls and empty strings

Result is a selection

  • 1
    Thanks! however, I am not being able to access it.
    – Fflavioo
    Mar 10, 2016 at 18:04
  • Hm, not sure. It's shared as public and already been downloaded 11 times... Mar 10, 2016 at 21:48
  • 1
    I click on it, and instead of opening the application I get the sign in page to New Gold Inc., which obviously I cannot access since I am not a member of the organization. Thanks!
    – Fflavioo
    Mar 14, 2016 at 14:23

You can try going through this:

enter image description here

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