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QUESTION: Hello Bob,

given that the ISNUMBER function returns false for a text string, even if the text string contains only numerical values, what is the best way to check whether a string contains only numerical values?

ie if it worked how I would like

=ISNUMBER("abc") would returns false, as it does

=ISNUMBER(123) would return true, as it does

but

=ISNUMBER("123") would return true, instead of false

ANSWER: =NOT(ISERROR(1*Range))

like

=NOT(ISERROR(1*A1)) or =NOT(ISERROR(1*"123"))

if A1 contained "123" then =NOT(ISERROR(1*"123")) would be =NOT(ISERROR(123)) which is =NOT(FALSE) which is TRUE.

If A contained "abc" then =NOT(ISERROR(1*"abc")) would be =NOT(ISERROR(#VALUE)) which is =NOT(TRUE) which is FALSE

HTH

---------- FOLLOW-UP ----------

QUESTION: Thanks Bob,

Now I'd like to do a similar thing in VBA. I wrote this function to test arg, if arg is a numeric string then the function should return a number, but if arg is non-numeric it should just return arg with no change. But it doesn't work :( It returns #VALUE when arg is not numeric, even when arg is "123".

Function ConvertNumber(arg As String)

If IsError(arg * 1) Then

ConvertNumber = arg 'if arg cannot be recognised as a number then return arg without change

Else

ConvertNumber = CDbl(arg) 'if arg can be recognised as a number then return the number as a value, not a string

End If

End Function

Function ConvertNumber(arg As String)

On Error Resume Next

n = arg * 1

If Err.Number <> 0 Then

ConvertNumber = arg 'if arg cannot be recognised as a number then return arg without change

Else

ConvertNumber = CDbl(arg) 'if arg can be recognised as a number then return the number as a value, not a string

End If

End Function

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Comment | Brilliant. Thanks for your help. |

This topic answers questions related to Microsoft Excel spreadsheet (or workbook) stand-alone or Mircrosoft Office Excel including Excel 2003, Excel 2007, Office 2000, and Office XP. You can get Excel help on Excel formulas(or functions), Excell macros, charting in Excel, advanced features, and the general use of Excel. This does not provide a general Excel tutorial nor the basics of using a spreadsheet. It provides specific answers to using Microsoft Excel only. If you do not see your Excel question answered in this area then please ask an Excel question here

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