How can we perform common set operations (union, intersection, minus) in MS Excel?

Question

For example, I have an xls where :

• column A has list of items with property A
• column B has list of items with property B

I need the fol

Answer 1

Intersection (In A & B): =IFNA(VLOOKUP(B2,$A$2:$B$42,1,FALSE),"")

Union (In A or B): =IFS(A2,A2,B2,B2) Note that IFS is only in recent (as of 2018) versions.

A - B (Only in A): =IF(NOT(IFNA(MATCH(A2,$B$2:$B$42,0),FALSE)),IF(A2,A2,""),"")

B - A (Only in B): =IF(NOT(IFNA(MATCH(B2,$A$2:$A$42,0),FALSE)),IF(B2,B2,""),"") (Swap the letters)

Answer 2

I'm surprised at several levels:
(1) 2020 now .... and still no set functions in Excel
(2) The highest voted answer (from 2018) is very impractical: in real live, data sets don't come neatly with empty rows inserted where a value is missing vs. another data set; which is the precondition for this solution.

The most practical solution (though still awkward; do you hear us, Microsoft ???) is a work around with the help of a pivot table:

• Add column to set A, with column name "set_name" and all values in the column set to "A" -> pivot input A
• Add column to set B, with column name "set_name" and all values in the column set to "B" -> pivot input B
• copy pivot input B (without column names ;-)) under pivot input A to form a joint range -> joint range
• create a pivot table from the joint range with
  --- "set names" being used to form the columns of the pivot table
  --- pivot function set to "count()"

The result is a sort of "one-hot-encoded" pivot table with:

• 1st column: union set of A and B (aka ALL occuring values)
• 2nd column: 1-values only for elements occuring in set A
  (caveat: assumption is that A only contains UNIQUE elements. Otherwise,
  values > 1 are possible)
• 3rd column: 1-values only for elements occuring in set B
  (same caveat applies as for set A)
• Total column: values showing "2" value exist in both sets

The resulting pivot table can easily be filtered on the different sets and intersections via the values in columns 2 (aka "set A"),3 (aka "set B") and 4 (aka "Set A AND Set B").

Answer 3

you can simple use below formula to get result

=IF(LOWER(A4)=LOWER(B4),"",A4)

Answer 4

Well, Microsoft Excel does not handle built-in set operations. But you can emulate then by VBA using MATCH function and error handling.

Here is the code that worked for me (I presume that you have heading on the first line):

Sub set_operations()
    Dim i, j, rangeA, rangeB, rowC, rowD, rowE, rowF As Long
    Dim test1, test2 As Boolean

    rangeA = ActiveSheet.Range("A" & CStr(ActiveSheet.Rows.Count)).End(xlUp).Row()
    rangeB = ActiveSheet.Range("B" & CStr(ActiveSheet.Rows.Count)).End(xlUp).Row()
    rowC = 2
    rowD = 2
    rowE = 2
    rowF = 2
    test1 = False
    test2 = False
    test2 = False

    'A union B
    On Error GoTo errHandler1
    For i = 2 To rangeA
        If Application.Match(ActiveSheet.Cells(i, 1), ActiveSheet.Range("C:C"), 0) > 0 Then
            If test1 = True Then
                ActiveSheet.Cells(rowC, 3) = ActiveSheet.Cells(i, 1)
                rowC = rowC + 1
            End If
        End If
        test1 = False
    Next i
    For j = 2 To rangeB
        If Application.Match(ActiveSheet.Cells(j, 2), ActiveSheet.Range("C:C"), 0) > 0 Then
            If test1 = True Then
                ActiveSheet.Cells(rowC, 3) = ActiveSheet.Cells(j, 2)
                rowC = rowC + 1
            End If
        End If
        test1 = False
    Next j

    'A intersection B
    For i = 2 To rangeA
        On Error GoTo errHandler2
        If Application.Match(ActiveSheet.Cells(i, 1), ActiveSheet.Range("B:B"), 0) > 0 Then
            On Error GoTo errHandler1
            If Application.Match(ActiveSheet.Cells(i, 1), ActiveSheet.Range("D:D"), 0) > 0 Then
                If test1 = True And test2 = False Then
                    ActiveSheet.Cells(rowD, 4) = ActiveSheet.Cells(i, 1)
                    rowD = rowD + 1
                End If
            End If
        End If
        test1 = False
        test2 = False
    Next i

    'A minus B
    For i = 2 To rangeA
        On Error GoTo errHandler2
        If Application.Match(ActiveSheet.Cells(i, 1), ActiveSheet.Range("B:B"), 0) > 0 Then
            On Error GoTo errHandler1
            If Application.Match(ActiveSheet.Cells(i, 1), ActiveSheet.Range("E:E"), 0) > 0 Then
                If test1 = True And test2 = True Then
                    ActiveSheet.Cells(rowE, 5) = ActiveSheet.Cells(i, 1)
                    rowE = rowE + 1
                End If
            End If
        End If
        test1 = False
        test2 = False
    Next i

    'B minus A
    For i = 2 To rangeB
        On Error GoTo errHandler2
        If Application.Match(ActiveSheet.Cells(i, 2), ActiveSheet.Range("A:A"), 0) > 0 Then
            On Error GoTo errHandler1
            If Application.Match(ActiveSheet.Cells(i, 2), ActiveSheet.Range("F:F"), 0) > 0 Then
                If test1 = True And test2 = True Then
                    ActiveSheet.Cells(rowF, 6) = ActiveSheet.Cells(i, 2)
                    rowF = rowF + 1
                End If
            End If
        End If
        test1 = False
        test2 = False
    Next i


errHandler1:
    test1 = True
    Resume Next

errHandler2:
    test2 = True
    Resume Next
End Sub