Is there a more concise regular expression to accomplish this task?

Posted by mpminnich on Stack Overflow See other posts from Stack Overflow or by mpminnich
Published on 2010-05-28T13:20:10Z Indexed on 2010/05/28 13:42 UTC
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First off, sorry for the lame title, but I couldn't think of a better one. I need to test a password to ensure the following:

Passwords must contain at least 3 of the following:

  • upper case letters
  • lower case letters
  • numbers
  • special characters

Here's what I've come up with (it works, but I'm wondering if there is a better way to do this):

    Dim lowerCase As New Regex("[a-z]")
    Dim upperCase As New Regex("[A-Z]")
    Dim numbers As New Regex("\d")
    Dim special As New Regex("[\\\.\+\*\?\^\$\[\]\(\)\|\{\}\/\'\#]")

    Dim count As Int16 = 0

    If Not lowerCase.IsMatch(txtUpdatepass.Text) Then
        count += 1
    End If
    If Not upperCase.IsMatch(txtUpdatepass.Text) Then
        count += 1
    End If
    If Not numbers.IsMatch(txtUpdatepass.Text) Then
        count += 1
    End If
    If Not special.IsMatch(txtUpdatepass.Text) Then
        count += 1
    End If

If at least 3 of the criteria have not been met, I handle it. I'm not well versed in regular expressions and have been reading numerous tutorials on the web. Is there a way to combine all 4 regexes into one? But I guess doing that would not allow me to check if at least 3 of the criteria are met.

On a side note, is there a site that has an exhaustive list of all characters that would need to be escaped in the regex (those that have special meaning - eg. $, ^, etc.)?

As always, TIA. I can't express enough how awesome I think this site is.

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