Regular Expression Help

Greg Griffiths · November 11th, 2004, 05:05 PM

Dear All,
I need to create a regex to validate a string to ensure that each character is either a letter, number of from a list of special characters in any order in the string. No other characters should be allowed.

Can anyone help ?

Snib · November 11th, 2004, 06:52 PM

Hey Greg,

I'm thinking it should look something like this:

[[A-Za-z0-9](\*|&|\(|\-)]+

or

([A-Za-z0-9](\*|&|\(|\-))+

These patterns should match any letter or digit, as well as *, &, (, and - (customize these for your characters).

But I'm new to regex's, maybe these are incorrect.

-Snib
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Greg Griffiths · November 11th, 2004, 07:44 PM

Snib,
thanks a lot for the reply, although that resolves the checking issue, it does not handle the check to ensure that at least one of each type - character, number & special char - are in the string.

joefawcett · November 12th, 2004, 04:28 AM

I think you just need all your allowed characters (for example %@!) in brackets with anchors:

Code:

^[\w\d%@!]+$

--

Joe (Microsoft MVP - XML)

ChrisScott · November 12th, 2004, 05:33 AM

Hi Greg,

If I understand you right, you want at least one of each of the digit group, alpha group and special characters in any order.
After playing about a bit, I came up with...

Code:

^([0-9]+(([a-zA-Z]+[0-9]*[Â£])|([Â£]+[0-9]*[a-zA-Z]))|[a-zA-Z]+(([0-9]+[a-zA-Z]*[Â£])|([Â£]+[a-zA-Z]*[0-9]))|[Â£]+(([0-9]+[Â£]*[a-zA-Z])|([a-zA-Z]+[Â£]*[0-9])))[0-9a-zA-ZÂ£]*$

which I think does what you're after (I used Â£ as a special character), not much fun to construct though, so I created the pattern using this...

Code:

function GetExp(specialChars){
    var digits = "0-9";
    var alphas = "a-zA-Z";
    var temp = "^(";
    temp += GetExpPart(digits, alphas, specialChars) + "|";
    temp += GetExpPart(alphas, digits, specialChars) + "|";
    temp += GetExpPart(specialChars, digits, alphas);
    temp += ")[" + digits + alphas + specialChars + "]*$"
    return temp;
}
function GetExpPart(pFirstGroup, pOtherGroup1, pOtherGroup2){
    return "[" + pFirstGroup + "]+(([" + pOtherGroup1 + "]+[" + pFirstGroup + "]*[" + pOtherGroup2 + "])" + 
            "|([" + pOtherGroup2 + "]+[" + pFirstGroup + "]*[" + pOtherGroup1 + "]))";
}

HTH,

Chris