checking existence of certain characters in a string

Actually I did find something on the web..

https://docs.microsoft.com/en-us/dotnet/visual-basic/programming-guide/language-features/strings/walkthrough-validating-that-passwords-are-complex

However I'm having problems deploying it..(see attached).

Perhaps I need to add some special references?

Thanks,
Ben
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did you add reference as

Imports System.Text.RegularExpressions

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Hi Huseyin,

Not sure how to go about that, as I usually add references thru the tools menu, see attached.

Thanks,
Ben
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first, add reference to "Microsoft VBScript Regular Expressions" library

As you can see on attached, I have that already.
FYI- This is to be used within an Access ADP project/MDB file as well, can you guide me?

Thanks,
Ben

try this

Dim rex As RegExp
Set rex = New RegExp
rex.Pattern = "^(?=.*[A-Za-z])(?=.*\d)(?=.*[\_+$@$!%*'#?&])[A-Za-z\d\_$+@$!%*'#?&]{8,}$$"
ValidatePassword=rex.Test(pwd)

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use this

^(?=.*[A-Za-z])(?=.*\d)(?=.*[\_+$@$!%*'#?&])[A-Za-z\d\_$+@$!%*'#?&]{8,}$

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https://regex101.com/

to test...

8 at the end is min length...
min 1 upper, min  1 lower, min 1 special character needed...

in this forum,

https://stackoverflow.com/questions/19605150/regex-for-password-must-be-contain-at-least-eight-characters-at-least-one-numbe

you can find lots of regex expression for different purposes...
just grab one that fits to your needs...
test it @ regex101.com
then use it in your function...

OK following your initial way I got it to work for a single occurance, as follows

Public Function ValidatePassword(ByVal pwd As String, Optional ByVal minLength As Integer = 8, Optional ByVal numUpper As Integer = 2, Optional ByVal numLower As Integer = 2, Optional ByVal numNumbers As Integer = 2, Optional ByVal numSpecial As Integer = 2) As Boolean

    ' Replace [A-Z] with \p{Lu}, to allow for Unicode uppercase letters.
    Dim rex As RegExp
Set rex = New RegExp
rex.Pattern = "[^A-Z]"
If Not rex.Test(pwd) Then
    ValidatePasswrod = False
    Exit Function
End If
rex.Pattern = "[a-z]"
If Not rex.Test(pwd) Then
    ValidatePasswrod = False
    Exit Function
End If
rex.Pattern = "[0-9]"
If Not rex.Test(pwd) Then
    ValidatePasswrod = False
    Exit Function
End If

ValidatePassword = True

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Now how do I convert the following?

'''    If upper.Matches(pwd).Count < numUpper Then Return False

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Thanks,
Ben

with above structure, use these...

rex.Pattern = "[a-z]" ' use one of below
If Not rex.Test(pwd) Then
    ValidatePasswrod = False
    Exit Function
End If

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1 upper: [A-Z]
1 lower: [a-z]
1 number: [0-9]
1 special listed: [\_+$@$!%*'#?&]

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or all in one shot like ID: 42202572

Not sure I got it.

Basically I need to know how do I get a number of occurrences, lets say we need 2 Upper Case letters, how do I check for that?

Thanks,
Ben

you should use this. 2 is the number of occurrence...

^(.*?[A-Z]){2,}

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and change [A-Z] with [a-z], [0-9], and list of special chars to test the others...

Great, this seems to work!
Just wondering, besides the 2 and the A-Z, what is the meaning of the other characters?

Thanks,
Ben

Thank you Huseyin!!

just go to https://regex101.com/
put some regex here and test it...
it will explain everything there...

or using vb function and loop :)

dim U as string = "ABC...Z"
dim L as string = "abc...z"
dim N as string = "01..9"
dim S as string = "?=-!..."

dim ux, lx, nx, sx as int
for i=0 to Lengh(pwd)
  dim c as string = substring(pwd,i,1)
  if U.indexOf(c)>=0 then ux=ux+1
  if L.indexOf(c)>=0 then lx=lx+1
  if N.indexOf(c)>=0 then nx=nx+1
  if S.indexOf(c)>=0 then sx=sx+1
next

if ux<2 then ...
if lx<2 then ...
if nx<1 then ...
if sx<1 then ...

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* not tested... shows just the logic...

The prior comment is VB.Net code.  You would have to change it to run in a VBA environment.

This comment submitted post-closure.
Here is a VBA-specific function that does not require a reference.

Function IsValidPwd(ByVal parmPwd As String) As Boolean
    'The Regex pattern enforces the following password rules:
    '1. must contain two or more upper case letters
    '2. must contain one or more lower case letters
    '3. must contain one or more numeric digits
    '4. must contain one or more non-alphanumeric/non-space characters (special chars)
    '5. password must be 8 or more characters long
    
    Static oRE As Object

    If oRE Is Nothing Then
        Set oRE = CreateObject("vbscript.regexp")
        oRE.Global = True
        oRE.Pattern = "^(?=(?:.*[A-Z]){2,})(?=(?:.*[a-z]){1,})(?=(?:.*\d){1,})(?=(?:.*[^ 0-9A-Za-z]){1,}).{8,}$"
    End If

    IsValidPwd = oRE.test(parmPwd)

End Function

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If you are dealing with a nullable password field, then concatenate an empty string to the password field value when invoking this function.

@aikimark

Here is a VBA-specific function that does not require a reference.

Thanks for that tip, will probably use that.
Ben