Array formula to return an ARRAY without duplicates, without VBA

Question

I would like to know whether it\'s possible to return an array from a single cell formula, which is filtered to remove duplicates, and which is built purely on Excel formulas.

Answer 1

Use this array formula to sum the unique, it requires the use of TEXTJOIN() which is only available with Office 365 Excel:

=SUM( IF(ISERROR(FIND(TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999+1,999)),MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),1,(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999))),--TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999+1,999))))

Being an array formula it needs to be confirmed with Ctrl-Shift-Enter instead of Enter when exiting edit mode.

You can replace SUM with many different formula.

If one does not have Office 365 Excel then vba and or helper columns are the only method available.

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Edit:

To remove the False from the array and return the 3rd non duplicate in the array we can wrap it in another TEXTJOIN:

=--TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,IF(ISERROR(FIND(TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999+1,999)),MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),1,(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999))),--TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999+1,999)),"")),(3-1)*999,999))

The 3 in the (3-1)*999 can be replaced by anything that returns the Index number desired.

Still an array formula that needs Ctrl-Shift-Enter.

If you want to return the relative position in then use this array:

=AGGREGATE(15,6,ROW(INDIRECT("1:" & COUNTA(A:A)))/(--TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,IF(ISERROR(FIND(TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999+1,999)),MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),1,(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999))),--TRIM(MID(TEXTJOIN(REPT(" ",999),TRUE,A:A),(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999+1,999)),"")),(ROW(INDIRECT("1:" & COUNTA(A:A)))-1)*999,999))=B1),1)

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I gave you the long formula for creating the array but for the sum:

=SUMPRODUCT(A1:A5/COUNTIF(A1:A5,A1:A5)) 

would be sufficient.

And for the Average:

=SUMPRODUCT(A1:A5/COUNTIF(A1:A5,A1:A5))/SUMPRODUCT(1/COUNTIF(A1:A5,A1:A5))

There are many work arounds that are shorter and better if you know what you want.