How to “flatten” or “collapse” a 2D Excel table into 1D?

Question

I have a two dimensional table with countries and years in Excel. eg.

        1961        1962        1963        1964
USA      a           x            g           


        

Answer 1

updated ReversePivotTable function so i can specify number of header columns and rows

Sub ReversePivotTable()
'   Before running this, make sure you have a summary table with column headers.
'   The output table will have three columns.
    Dim SummaryTable As Range, OutputRange As Range
    Dim OutRow As Long
    Dim r As Long, c As Long

    Dim lngHeaderColumns As Long, lngHeaderRows As Long, lngHeaderLoop As Long

    On Error Resume Next
    Set SummaryTable = ActiveCell.CurrentRegion
    If SummaryTable.Count = 1 Or SummaryTable.Rows.Count < 3 Then
        MsgBox "Select a cell within the summary table.", vbCritical
        Exit Sub
    End If
    SummaryTable.Select

    Set OutputRange = Application.InputBox(prompt:="Select a cell for the 3-column output", Type:=8)
    lngHeaderColumns = Application.InputBox(prompt:="Header Columns")
    lngHeaderRows = Application.InputBox(prompt:="Header Rows")
'   Convert the range
    OutRow = 2
    Application.ScreenUpdating = False
    'OutputRange.Range("A1:D3") = Array("Column1", "Column2", "Column3", "Column4")
    For r = lngHeaderRows + 1 To SummaryTable.Rows.Count
        For c = lngHeaderColumns + 1 To SummaryTable.Columns.Count
            ' loop through all header columns and add to output
            For lngHeaderLoop = 1 To lngHeaderColumns
                OutputRange.Cells(OutRow, lngHeaderLoop) = SummaryTable.Cells(r, lngHeaderLoop)
            Next lngHeaderLoop
            ' loop through all header rows and add to output
            For lngHeaderLoop = 1 To lngHeaderRows
                OutputRange.Cells(OutRow, lngHeaderColumns + lngHeaderLoop) = SummaryTable.Cells(lngHeaderLoop, c)
            Next lngHeaderLoop

            OutputRange.Cells(OutRow, lngHeaderColumns + lngHeaderRows + 1) = SummaryTable.Cells(r, c)
            OutputRange.Cells(OutRow, lngHeaderColumns + lngHeaderRows + 1).NumberFormat = SummaryTable.Cells(r, c).NumberFormat
            OutRow = OutRow + 1
        Next c
    Next r
End Sub