String variable

How can I determine if a String variable contains a valid string? For numeric variables I can use IsNumeric, is there something similar for text?

What do you consider a "valid string"? You could check for characters that you don't want or characters that you must have by using InStr.

I would consider a valid string anything containing ascii codes 32 - 126.

1) How do I traverse through each letter in a string?
2) How do I convert a letter to an ascii code in vb?

My vb is a little rough I'm used to c++.

You could try the following:

Code:

---

dim x as integer
dim strCharacter as string
dim lglValidString as boolean

for x = 1 to len(string)
  strCharacter = mid$(string,x,1)
  if asc(strCharacter) > 31 or asc(strCharacter) < 127 then
        lglValidString = True
  Else
        lglValidString = False
        Exit For
  End If
Next

If Not lglValid String Then
......
End If

---

HTH

JP

the following function replaces anything that is not in the range 0 to 9 or 'a' to 'z' with a minus sign:

Code:

---

Private Sub cleanseBackupComment()
  backupComment = LCase$(backupComment)
  backupComment = Replace$(backupComment, " ", "_")
  'clean the comment up.. replace all chars not in 0 - 9 to a - z with a minus
  Dim charNum As Integer
 
  'up to 0
  For charNum = &H0 To &H2F
    backupComment = Replace$(backupComment, Chr$(charNum), "-")
  Next charNum
  'from 9 to underscore (5F)
  For charNum = &H3A To &H5E
    backupComment = Replace$(backupComment, Chr$(charNum), "-")
  Next charNum
  backupComment = Replace$(backupComment, Chr$(&H60), "-")
  'from z to 255
  For charNum = &H7B To &HFF
    backupComment = Replace$(backupComment, Chr$(charNum), "-")
  Next charNum
End Sub

---

the opposite of Chr$() is Asc()

supply chr with a number, it gives a character. supply chr$ with a number, it gives a string of that character, supply asc with a one char string and it gives a number of that string/char:

Chr$(32) -> " "
Asc(" ") -> 32

asc only works on the first given character, so Asc(" abc") only gives 32 for the initial space

AscW is the Unicode version

Thanks that's exactly what I was looking for. :thumb: