Determining duplicate entries and frequency

**Tissy** · 03-20-2009, 12:46 PM

Hi, this is my first post, so i hope i have posted in the correct place.

I have been using excel for a while now but only for simple spreadsheet applications.

I have a worksheet which consists of 9 columns of alphanumeric data (columns A - I) which each contains alphanumeric data. Each column may have upto 2000 enteries.

The data generally consists of an alphanumeric string consisting of no more than 7 characters.

For example:

ABC123D
CDE456F
DFR789R

etc

Each column does have unique strings, however each columns is obvioulsy different.

Contained within some of the coumns may be some alphanumeric strings which are also present in other columns.

How would one find a way of establishing what these common strings are in each of the columns and presenting their frequency. It could be the case that a common string only appears in 4 out of the 9 sheets and may consist of more than one common string.

So for example in column M I would like to present on the duplicate strings which are present in the columns along with their respective frequency of occurance.

For example.

ABC123D - 5
CEF543E - 3

And so on.

Any help would be greatfully appriciated as this is a bit beyond me.

Steve

**NBVC** · 03-20-2009, 01:47 PM

Countif() counts the number of times a certain string occurs amongst a range.. maybe you can adapt that function? See Excel help on the Countif function for details.

**Tissy** · 03-20-2009, 01:58 PM

Unfortunatly each string within a column length of 2000 enteries is different.

I guess this command is easy to use if you only want to count 1 or 2 known strings within the range.

I need to find out which strings are common (and their frequency) against 9 columns each consisting of around 2000 enteries. So finding possibily multiple duplicates in around 18000 enteries.

**JBeaucaire** · 03-20-2009, 02:04 PM

This is an ugly macro, but it works, run it and stretch, it would probably take a minute or more on that much data:

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The result will be Column M has items with duplicates, column N has the frequency count of those duplicates.

**NBVC** · 03-20-2009, 02:04 PM

Say your 9-column range is A1:I2000

In M1, put formula:

=IF(COUNTIF($A$1:$I$2000,A1)>1,A1,"")

copy it across 9 columns and down to row 2000.

If you have duplicates it will show you what is it and exactly where it is.

Or if you just want total counts, use:

=COUNTIF($A$1:$I$2000,A1) anything greater that 1 is duplicated.

**Leith Ross** · 03-20-2009, 10:08 PM

Hello Tissy,

Here is another option. This macro will return a list of the duplicates with their frequency (2 or higher). It will work with all types of cell data, except cells that my contain arrays. It has been setup to look at cells "A1:I2000" on "Sheet1" and put list on "Sheet2" starting with cell "A1". You can change the location of the data and duplicate list. They are marked in red in the code.

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Adding the Macro
1. Copy the macro above pressing the keys CTRL+C
2. Open your workbook
3. Press the keys ALT+F11 to open the Visual Basic Editor
4. Press the keys ALT+I to activate the Insert menu
5. Press M to insert a Standard Module
6. Paste the code by pressing the keys CTRL+V
7. Make any custom changes to the macro if needed at this time.
8. Save the Macro by pressing the keys CTRL+S
9. Press the keys ALT+Q to exit the Editor, and return to Excel.

To Run the Macro...
To run the macro from Excel, open the workbook, and press ALT+F8 to display the Run Macro Dialog. Double Click the macro's name to Run it.