Convert string to int if string is a number - excel

Question

I need to convert a string, obtained from excel, in VBA to an interger. To do so I'm using CInt() which works well. However there is a chance that the string could be something other than a number, in this case I need to set the integer to 0. Currently I have:
If oXLSheet2.Cells(4, 6).Value <> "example string" Then
currentLoad = CInt(oXLSheet2.Cells(4, 6).Value)
Else
currentLoad = 0
End If
The problem is that I cannot predict all possible non numeric strings which could be in this cell. Is there a way I can tell it to convert if it's an integer and set to 0 if not?

Answer 1

Use IsNumeric. It returns true if it's a number or false otherwise.
Public Sub NumTest()
On Error GoTo MyErrorHandler
Dim myVar As Variant
myVar = 11.2 'Or whatever
Dim finalNumber As Integer
If IsNumeric(myVar) Then
finalNumber = CInt(myVar)
Else
finalNumber = 0
End If
Exit Sub
MyErrorHandler:
MsgBox "NumTest" & vbCrLf & vbCrLf & "Err = " & Err.Number & _
vbCrLf & "Description: " & Err.Description
End Sub

Answer 2

Cast to long or cast to int, be aware of the following.
These functions are one of the view functions in Excel VBA that are depending on the system regional settings. So if you use a comma in your double like in some countries in Europe, you will experience an error in the US.
E.g., in european excel-version 0,5 will perform well with CDbl(), but in US-version it will result in 5.
So I recommend to use the following alternative:
Public Function CastLong(var As Variant)
' replace , by .
var = Replace(var, ",", ".")
Dim l As Long
On Error Resume Next
l = Round(Val(var))
' if error occurs, l will be 0
CastLong = l
End Function
' similar function for cast-int, you can add minimum and maximum value if you like
' to prevent that value is too high or too low.
Public Function CastInt(var As Variant)
' replace , by .
var = Replace(var, ",", ".")
Dim i As Integer
On Error Resume Next
i = Round(Val(var))
' if error occurs, i will be 0
CastInt = i
End Function
Of course you can also think of cases where people use commas and dots, e.g., three-thousand as 3,000.00. If you require functionality for these kind of cases, then you have to check for another solution.

Answer 3

Try this:
currentLoad = ConvertToLongInteger(oXLSheet2.Cells(4, 6).Value)
with this function:
Function ConvertToLongInteger(ByVal stValue As String) As Long
On Error GoTo ConversionFailureHandler
ConvertToLongInteger = CLng(stValue) 'TRY to convert to an Integer value
Exit Function 'If we reach this point, then we succeeded so exit
ConversionFailureHandler:
'IF we've reached this point, then we did not succeed in conversion
'If the error is type-mismatch, clear the error and return numeric 0 from the function
'Otherwise, disable the error handler, and re-run the code to allow the system to
'display the error
If Err.Number = 13 Then 'error # 13 is Type mismatch
Err.Clear
ConvertToLongInteger = 0
Exit Function
Else
On Error GoTo 0
Resume
End If
End Function
I chose Long (Integer) instead of simply Integer because the min/max size of an Integer in VBA is crummy (min: -32768, max:+32767). It's common to have an integer outside of that range in spreadsheet operations.
The above code can be modified to handle conversion from string to-Integers, to-Currency (using CCur() ), to-Decimal (using CDec() ), to-Double (using CDbl() ), etc. Just replace the conversion function itself (CLng). Change the function return type, and rename all occurrences of the function variable to make everything consistent.

Answer 4

Just use Val():
currentLoad = Int(Val([f4]))
Now currentLoad has a integer value, zero if [f4] is not numeric.

Answer 5

To put it on one line:
currentLoad = IIf(IsNumeric(oXLSheet2.Cells(4, 6).Value), CInt(oXLSheet2.Cells(4, 6).Value), 0)

Answer 6

Here are a three functions that might be useful. First checks the string for a proper numeric format, second and third function converts a string to Long or Double.
Function IsValidNumericEntry(MyString As String) As Boolean
'********************************************************************************
'This function checks the string entry to make sure that valid digits are in the string.
'It checks to make sure the + and - are the first character if entered and no duplicates.
'Valid charcters are 0 - 9, + - and the .
'********************************************************************************
Dim ValidEntry As Boolean
Dim CharCode As Integer
Dim ValidDigit As Boolean
Dim ValidPlus As Boolean
Dim ValidMinus As Boolean
Dim ValidDecimal As Boolean
Dim ErrMsg As String
ValidDigit = False
ValidPlus = False
ValidMinus = False
ValidDecimal = False
ValidEntry = True
For x = 1 To Len(MyString)
CharCode = Asc(Mid(MyString, x, 1))
Select Case CharCode
Case 48 To 57 ' Digits 0 - 9
ValidDigit = True
Case 43 ' Plus sign
If ValidPlus Then 'One has already been detected and this is a duplicate
ErrMsg = "Invalid entry....too many plus signs!"
ValidEntry = False
Exit For
ElseIf x = 1 Then 'if in the first positon it is valide
ValidPlus = True
Else 'Not in first position and it is invalid
ErrMsg = "Invalide entry....Plus sign not in the correct position! "
ValidEntry = False
Exit For
End If
Case 45 ' Minus sign
If ValidMinus Then 'One has already been detected and this is a duplicate
ErrMsg = "Invalide entry....too many minus signs! "
ValidEntry = False
Exit For
ElseIf x = 1 Then 'if in the first position it is valid
ValidMinus = True
Else 'Not in first position and it is invalid
ErrMsg = "Invalide entry....Minus sign not in the correct position! "
ValidEntry = False
Exit For
End If
Case 46 ' Period
If ValidDecimal Then 'One has already been detected and this is a duplicate
ErrMsg = "Invalide entry....too many decimals!"
ValidEntry = False
Exit For
Else
ValidDecimal = True
End If
Case Else
ErrMsg = "Invalid numerical entry....Only digits 0-9 and the . + - characters are valid!"
ValidEntry = False
Exit For
End Select
Next
If ValidEntry And ValidDigit Then
IsValidNumericEntry = True
Else
If ValidDigit = False Then
ErrMsg = "Text string contains an invalid numeric format." & vbCrLf _
& "Use only one of the following formats!" & vbCrLf _
& "(+dd.dd -dd.dd +dd -dd dd.d or dd)! "
End If
MsgBox (ErrMsg & vbCrLf & vbCrLf & "You Entered: " & MyString)
IsValidNumericEntry = False
End If
End Function
Function ConvertToLong(stringVal As String) As Long
'Assumes the user has verified the string contains a valide numeric entry.
'User should call the function IsValidNumericEntry first especially after any user input
'to verify that the user has entered a proper number.
ConvertToLong = CLng(stringVal)
End Function
Function ConvertToDouble(stringVal As String) As Double
'Assumes the user has verified the string contains a valide numeric entry.
'User should call the function IsValidNumericEntry first especially after any user input
'to verify that the user has entered a proper number.
ConvertToDouble = CDbl(stringVal)
End Function