Extract a list of duplicates from two columns combined
The following regular formula extracts duplicates from column B (List1) and column D (List2) combined, the result is shown in column F.
Formula in cell F3:
Explaining formula in cell F3
This formula consists of two similar parts, one returns values from List1 and the other returns values from List2.
IFERROR(formula1, formula2)
Step 1 - Prevent duplicate values
The COUNTIF function counts values based on a condition, in this case, I am counting values in cells above. This makes sure that duplicates are ignored.
COUNTIF($F$2:F2,$B$3:$B$21)=0
becomes
COUNTIF("Duplicates",$B$3:$B$21)=0
becomes
COUNTIF("Duplicates",{"Federer, Roger ";"Djokovic, Novak ";"Murray, Andy ";"Davydenko, Nikolay ";"Roddick, Andy ";"Del Potro, Juan Martin ";"Federer, Roger ";"Davydenko, Nikolay ";"Verdasco, Fernando ";"Gonzalez, Fernando ";"Wawrinka, Stanislas ";"Gonzalez, Fernando ";"Blake, James ";"Nalbandian, David ";"Robredo, Tommy ";"Wawrinka, Stanislas ";"Cilic, Marin ";"Stepanek, Radek ";"Almagro, Nicolas "})=0
{0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0;0}=0
and returns
{TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE}
Step 2 - Count values in List1
We want to know where the duplicates are if there are any.
COUNTIF($B$3:$B$21,$B$3:$B$21)>1
becomes
COUNTIF({"Federer, Roger ";"Djokovic, Novak ";"Murray, Andy ";"Davydenko, Nikolay ";"Roddick, Andy ";"Del Potro, Juan Martin ";"Federer, Roger ";"Davydenko, Nikolay ";"Verdasco, Fernando ";"Gonzalez, Fernando ";"Wawrinka, Stanislas ";"Gonzalez, Fernando ";"Blake, James ";"Nalbandian, David ";"Robredo, Tommy ";"Wawrinka, Stanislas ";"Cilic, Marin ";"Stepanek, Radek ";"Almagro, Nicolas "},{"Federer, Roger ";"Djokovic, Novak ";"Murray, Andy ";"Davydenko, Nikolay ";"Roddick, Andy ";"Del Potro, Juan Martin ";"Federer, Roger ";"Davydenko, Nikolay ";"Verdasco, Fernando ";"Gonzalez, Fernando ";"Wawrinka, Stanislas ";"Gonzalez, Fernando ";"Blake, James ";"Nalbandian, David ";"Robredo, Tommy ";"Wawrinka, Stanislas ";"Cilic, Marin ";"Stepanek, Radek ";"Almagro, Nicolas "})>1
becomes
{2;1;1;2;1;1;2;2;1;2;2;2;1;1;1;2;1;1;1}>1
{TRUE;FALSE; FALSE;TRUE; FALSE;FALSE; TRUE;TRUE; FALSE;TRUE; TRUE;TRUE; FALSE;FALSE; FALSE;TRUE; FALSE;FALSE; FALSE}
Step 3 - Multiply arrays
(COUNTIF($F$2:F2,$B$3:$B$21)=0)*(COUNTIF($B$3:$B$21,$B$3:$B$21)>1)
becomes
{TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE; TRUE;TRUE;TRUE;TRUE} * {TRUE;FALSE; FALSE;TRUE; FALSE;FALSE; TRUE;TRUE; FALSE;TRUE; TRUE;TRUE; FALSE;FALSE; FALSE;TRUE; FALSE;FALSE; FALSE}
and returns
{1;0;0;1;0;0;1;1;0;1;1;1;0;0;0;1;0;0;0}
Step 4 - Divide 1 with array
The LOOKUP function ignores error and if we divide 1 with 0 an error occurs. 1/0 = #DIV/0!
1/((COUNTIF($F$2:F8,$B$3:$B$21)=0)*(COUNTIF($B$3:$B$21,$B$3:$B$21)>1))
becomes
1/{1;0;0;1;0;0;1;1;0;1;1;1;0;0;0;1;0;0;0}
and returns
{1;#DIV/0!;#DIV/0!;1;#DIV/0!;#DIV/0!;1;1;#DIV/0!;1;1;1;#DIV/0!;#DIV/0!;#DIV/0!;1;#DIV/0!;#DIV/0!;#DIV/0!}
Step 5 - Return value based on array
LOOKUP(2, 1/((COUNTIF($F$2:F2,$B$3:$B$21)=0)*(COUNTIF($B$3:$B$21,$B$3:$B$21)>1)), $B$3:$B$21)
becomes
LOOKUP(2, 1/{1;0;0;1;0;0;1;1;0;1;1;1;0;0;0;1;0;0;0}, $B$3:$B$21)
becomes
LOOKUP(2, 11/{1;0;0;1;0;0;1;1;0;1;1;1;0;0;0;1;0;0;0}, {"Federer, Roger ";"Djokovic, Novak ";"Murray, Andy ";"Davydenko, Nikolay ";"Roddick, Andy ";"Del Potro, Juan Martin ";"Federer, Roger ";"Davydenko, Nikolay ";"Verdasco, Fernando ";"Gonzalez, Fernando ";"Wawrinka, Stanislas ";"Gonzalez, Fernando ";"Blake, James ";"Nalbandian, David ";"Robredo, Tommy ";"Wawrinka, Stanislas ";"Cilic, Marin ";"Stepanek, Radek ";"Almagro, Nicolas "})
and returns Wawrinka, Stanislas in cell F3.
Step 6 - Return values from List2
When values run out from List1 formula1 returns errors, the IFERROR function then moves to formula2.
IFERROR(formula1, formula2)
formula2 is just like formula1 except that it returns values from List2 and duplicates found between List1 and List2.
Earlier Excel versions:
Download Excel *.xlsx
how-to-extract-a-list of duplicates from two columns-in-excelv2.xlsx
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2 Responses to “Extract a list of duplicates from two columns combined”
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Hello,
I have duplicate data spread between C3 and W22. I would like to list the distinct values in C3:W22 in another worksheet(2003). could you please help me.
Regards,
Kamal
Hi Oscar,
I am having issues with the listing formula, I have a table as below:
S.no Month Date Session Name Session Duration Trainer
1 Sep 05-Sep-14 The Art of Tactful conversations 0.5 ABC
2 Sep 09-Sep-14 Managing Client Expectations 0.5 DEF
3 Sep 11-Sep-14 Creativity and Lateral Thinking 0.5 SBC
4 Sep 15 Sep14 and 16 Sep Shaping Customer Agenda 2 days ABC
5 Sep 16-Sep-14 The Art of Presentation Skills 0.5 SBC
6 Sep 23-Sep-14 Happiness @ Work 0.5 ABC
7 Sep 25-Sep-14 Emotional Intelligence 1 day DEF
8 Sep 29-Sep-14 Influencing and Negotiation skills 0.5 DEF
9 Sep 29-Sep-14 Planning and Prioritisation 0.5 SBC
10 Sep 30-Sep-14 Strengthening Workplace relations 0.5 ABC
I need to get a list of trainings done if i update a trainers name.
This has to be done in a seperate workbook.
Please help.
Thanks
DS