Regex help

[rivan]

I'm a total code hack - I'll admit up front.

I've got a bit of regex to validate a form field as a valid email address (within our company) but I'd like it to validate OK if left blank as well.

Take this generic email validation:
([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3})

How would I modify that to include an "or (null)"?

 

[Tencntraze]

Could you just hack it by wrapping the entire thing in parenthesis and a *, meaning 0 or more of that block? This is just off the top of my head without testing

 

[Ken g6]

I'm a total code hack - I'll admit up front.

I've got a bit of regex to validate a form field as a valid email address (within our company) but I'd like it to validate OK if left blank as well.

Take this generic email validation:
([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3})

How would I modify that to include an "or (null)"?

([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3})|

I assume ^ and $ are implied?

^(([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3})|)$

@Tencntraze, you mean a ?.

(([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3}))?

 

[Tencntraze]

@Tencntraze, you mean a ?.([a-zA-Z]{3}))?

* means 0 or more while ? means 0 or 1, right? I guess they'd both work in his case, but if he wants to prevent multiple e-mail addresses in the same line then ? would be better

 

[rivan]

([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3})|

I assume ^ and $ are implied?

^(([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3})|)$

@Tencntraze, you mean a ?.

(([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{3}))?

As I mentioned, I'm a complete hack - I can pick apart the bulk of how what I have functions, but not have a full understanding of what I'm reading.

I know it functions in my application without the beginning- or end-of-string flags.

So, just to make sure I'm reading what I think I am, you took what I pasted, added the pipe as 'or', then nothing to function as the null match, and wrapped the set in parens?

 

[Ken g6]

* means 0 or more while ? means 0 or 1, right?

Yes.

So, just to make sure I'm reading what I think I am, you took what I pasted, added the pipe as 'or', then nothing to function as the null match, and wrapped the set in parens?

Yes. And I added ^ and $ to make sure it matches the beginning and end of the string. Without them, and with this change, anything could appear in the string!

 

[rivan]

Could you just hack it by wrapping the entire thing in parenthesis and a *, meaning 0 or more of that block? This is just off the top of my head without testing

Thanks for giving it a shot - this didn't work (though I can't help but wonder if it wasn't just my CMS).

Yes. And I added ^ and $ to make sure it matches the beginning and end of the string. Without them, and with this change, anything could appear in the string!

Perfect - it's up and running - thanks for your help!