Regex match 2 out of 4 groups

Question

I want a single Regex expression to match 2 groups of lowercase, uppercase, numbers or special characters. Length needs to also be grater than 7.

I currently have this expression

^(?=.*[^a-zA-Z])(?=.*[a-z])(?=.*[A-Z]).{8,}$

It, however, forces the string to have lowercase and uppercase and digit or special character.

I currently have this implemented using 4 different regex expressions that I interrogate with some C# code.

I plan to reuse the same expression in JavaScript.

This is sample console app that shows the difference between 2 approaches.

class Program
{
    private static readonly Regex[] Regexs = new[] {
        new Regex("[a-z]", RegexOptions.Compiled), //Lowercase Letter
        new Regex("[A-Z]", RegexOptions.Compiled), // Uppercase Letter
        new Regex(@"\d", RegexOptions.Compiled), // Numeric
        new Regex(@"[^a-zA-Z\d\s:]", RegexOptions.Compiled) // Non AlphaNumeric
    };

    static void Main(string[] args)
    {
        Regex expression = new Regex(@"^(?=.*[^a-zA-Z])(?=.*[a-z])(?=.*[A-Z]).{8,}$", RegexOptions.ECMAScript & RegexOptions.Compiled);

        string[] testCases = new[] { "P@ssword", "Password", "P2ssword", "xpo123", "xpo123!", "xpo123!123@@", "Myxpo123!123@@", "Something_Really_Complex123!#43@2*333" };

        Console.WriteLine("{0}\t{1}\t", "Single", "C# Hack");
        Console.WriteLine("");
        foreach (var testCase in testCases)
        {
            Console.WriteLine("{0}\t{2}\t : {1}", expression.IsMatch(testCase), testCase, 
                    (testCase.Length >= 8 && Regexs.Count(x => x.IsMatch(testCase)) >= 2));
        }

        Console.ReadKey();
    }
}

Result  Proper     Test String
------- -------    ------------

True    True     : P@ssword
False   True     : Password
True    True     : P2ssword
False   False    : xpo123
False   False    : xpo123!
False   True     : xpo123!123@@
True    True     : Myxpo123!123@@
True    True     : Something_Really_Complex123!#43@2*333

Answer 1

For javascript you can use this pattern that looks for boundaries between different character classes:

^(?=.*(?:.\b.|(?i)(?:[a-z]\d|\d[a-z])|[a-z][A-Z]|[A-Z][a-z]))[^:\s]{8,}$

if a boundary is found, you are sure to have two different classes.

pattern details:

\b # is a zero width assertion, it's a boundary between a member of 
   # the \w class and an other character that is not from this class.

.\b. # represents the two characters with the word boundary.

boundary between a letter and a number:

(?i) # make the subpattern case insensitive
(?:
    [a-z]\d # a letter and a digit
  |         # OR
    \d[a-z] # a digit and a letter
)

boundary between an uppercase and a lowercase letter:

[a-z][A-Z] | [A-Z][a-z]

since all alternations contains at least two characters from two different character classes, you are sure to obtain the result you hope.