Combining these two Regular Expressions into one

Question

I have the following in C#:

public static bool IsAlphaAndNumeric(string s)
{
    return Regex.IsMatch(s, @\"[a-zA-Z]+\") 
        && Regex.IsMatch(s,         


        

Answer 1

private static readonly Regex _regex = new Regex(
    @"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).+$", RegexOptions.Compiled);

public static bool IsAlphaAndNumeric(string s)
{
    return _regex.IsMatch(s);
}

If you want to ignore case you could use RegexOptions.Compiled | RegexOptions.IgnoreCase.