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Hack 73 Convert Numbers with the Negative Sign on the Right to Excel Numbers

Have you ever had to work with imported
negative numbers that have the negative sign on the right? SAP is one
such program that does this with negative numberse.g., 200-
instead of -200. Changing these by hand so that Excel understands
them can be a hassle, but it doesn't need to
be.

Say
you have a long list of numbers you just imported and some of them
are those so-called negative numbers. Your job is to convert these to
valid negatives that Excel will recognize. For the purposes of this
exercise, you will use the range A1:A100. In cell B1, enter this
formula:

=SUBSTITUTE(IF(RIGHT(TRIM(A1))="-",RIGHT(TRIM(A1))&A1,A1),"-",",2)+0

Enter this as many cells down the column
as needed and then copy them and select cell A1. Select Edit
Paste Special... Values to remove the formula
and retain the values only. Figure 6-16 shows a
before-and-after example (A1:A7 represents before).

Figure 6-16. Before and after moving the negative sign

To give you an idea of how the formula works, enter the following
formula in any cell where A1 has the text 200-:

=RIGHT(TRIM(A1),1)&A1

You will end up with -200-.

The TRIM function
simply ensures that there are no space characters in the cell. As you
end up with -200-, you need to remove the second occurrence of the
negative sign. This is what the SUBSTITUTE
function is doing. You told it to substitute the second occurrence of
- with " (empty text). The
result returned is actually text (as that is what the
SUBSTITUTE function returns), so you simply use
+0, and Excel will convert it to a number.

If you need to do this frequently, you
should consider a macro to make the job easier. Here is one that will
do the task at hand. It has been optimized for speed.

Sub ConvertMirrorNegatives( )
Dim rCell As Range
Dim rRange As Range
Dim lCount As Long
Dim lLoop As Long
'Ensure they have the data selected and display a message if they _
don't, then exit the macro.
If Selection.Cells.Count = 1 Then
MsgBox "Please select the range to convert", vbInformation
Exit Sub
End If
'Set a variable to ONLY text cells, e.g., 200-
On Error Resume Next
Set rRange = Selection.SpecialCells(xlCellTypeConstants, xlTextValues)
'If our variable returns Nothing, there are no incorrect negatives _
so display a message, then exit the macro
If rRange Is Nothing Then
MsgBox "No mirror negatives found", vbInformation
On Error GoTo 0
Exit Sub
End If
'Count just how many cells are like 200- and pass this number _
to a variable to control how many loops are needed.
lCount = WorksheetFunction.CountIf(Selection, "*-")
'Set a variable to the first cell in the selection
Set rCell = Selection.Cells(1, 1)
'Loop only as many times as there are incorrect negatives
For lLoop = 1 To lCount
'At each loop set a variable to the cell housing *-
'The asterisk is a wildcard character
Set rCell = rRange.Find(What:="*-", After:=rCell, _
LookIn:=xlValues, LookAt:=xlPart, _
SearchOrder:=xlByRows, SearchDirection:= _
xlNext, MatchCase:=False)
'Use the standard Replace feature to replace the negative sign _
with nothing. In other words, we remove it.
rCell.Replace What:="-", Replacement:="
'Multiply the cell by -1 to convert it to a negative number
rCell = rCell * -1
Next lLoop
On Error GoTo 0
End Sub

To use this macro, select
Tools Macro Visual Basic Editor (or
Alt/Option-F11). Now select Insert Module and paste in the
preceding code. Close the window to return to Excel and select Tools
Macro Macros, and then select Convert Mirror
Negatives. Click Options and assign a shortcut key. Now when you have
to convert those imported negatives to true negatives that Excel will
recognize, simply select the figures and use your shortcut
key.