Question

Please Help me in creating a replace function.
Problem:
Their is a alphanumeric value of any length (string) and I want to replace its all characters with ‘X’ except right four characters

Like :
Value : 4111111111111111
Result Should be: XXXXXXXXXXXX1111

I have created a function but got stuck:

public function myfunction(str as string)
  str.Replace(str.Substring(0, str.Length - 5), 'X') 'but here I want no of x to be equals to count of length of str - 4
end function

What’s a better function to perform such an operation?

Answer 1

Try this on for size.

Public Shared Function ObfuscateCardNumber(ByVal cardNumber As String) As String
    If cardNumber.Length <= 4 Then
        Return cardNumber
    Else
        Return cardNumber _
            .Substring(cardNumber.Length - 4, 4) _
            .PadLeft(cardNumber.Length, "X"c)
    End If
End Function