Reg Exp for @www.webinspect.hp.com

[Nitin Singla]

Hi,


String str="@www.webinspect.hp.com";

I need to use a reg exp pattern for detecting @www.webinspect.hp.com for str.

Can anybody help me what should be the regexp for this type of string please?

[fred rosenberger]

What have you tried?

[Henry Wong]

Another point is... if you are looklng for an exact string, you don't need regular expressions. There are methods of the string class that can check if a string contains a particular string value.

Henry

[Nitin Singla]

hi
thanks for the reply..

str="@www.webinspect.hp.com";

is one example.. i just need one regexp for checking strings containing values like the one above in str..

[Winston Gutkowski]

Nitin Singla wrote:is one example.. i just need one regexp for checking strings containing values like the one above in str.

Then you need to explain precisely what you mean by "values like". In fact, it'll be a big help in working out the regex for yourself.

Winston

[Nitin Singla]

Hi,

I mean to say str can be like

str="@****.com" -- where * denotes A-Z, a-z

examples:
str="@www.abc.com";
str="@www.webinspect.hp.com";
str="@www.def.com";
............


I am new to java and I am learning but i need this regexp. Please help.

[fred rosenberger]

We ARE helping. What we don't do is just give out an answer.

It is still not clear what you mean. I THINK you mean:

a literal '@' symbol

some number of alphabetics (what is the lower and upper limit?)

followed by the literal ".com"

However, your examples contradict what you state:

"@****.com" -- where * denotes A-Z, a-z

The, your example "@www.webinspect.hp.com" contradicts this. You say a '*' is a alphabetic, but this example has a '.' in it, between "webinspect" and "hp".

At the very least, you should give it a shot, and post what you try here.

[Nitin Singla]

Thanks for correcting me sir.
Let me write it very carefully this time:

Format for url:

str="@***.**.**.com"

Correct example is below:

str="@www.webinspect.hp.com";


I need a regexp for the above type of format. Can anybody help me out here?
Thanks in advance.

[Junilu Lacar]

So, tell us what you came up with after you have gone through some of the links found by this search: regex tutorial

[Jesper de Jong]

Nitin Singla wrote:Format for url:

str="@***.**.**.com"

Aha. So @www.abc.com does not match? (Above, you said it should match). Because @www.abc.com does not have two dots before the ".com".

The point is, you need to exactly specify the rules. Once you've done that, you can formulate it as a regular expression. It's not good enough to say "it should be more or less like this". Computers only do exactly what you tell them to do - they can't work with approximate rules.

Have you already looked up the syntax for regular expressions in Java? So, what is your best guess for a regular expression for your case?

[Michael Krimgen]

to help you to find the correct regular expression, I suggest you think that way:

"between the @ and the .com you need a string which consits of only characters (and numbers or special characters like _ ?) and dots. Furthermore, there should only be single dots
and no dot at the beginning or the end of the string".

However, there might be more conditions, depending on what exactly you want.

Hope that helps a bit!

Michael

[Nitin Singla]

I come up with this :

@([\w-]+\.)+[\w-]*

Please correct me if I am going in wrong direction?
But I am just asking for a help.. not for any humilation for beginners in java...

thanks

[Henry Wong]

Nitin Singla wrote:I come up with this :

@([\w-]+\.)+[\w-]*

Please correct me if I am going in wrong direction?
But I am just asking for a help.. not for any humilation for beginners in java...

thanks

There is a reason why we are being that exact, even to the point of being anal. And it is not for humiliation. The reason is, regular expressions needs to be exact. It is amazing how many situations are obvious to you, where it isn't to regular expressions.

Anyway, what happened when you ran that regex? Did it work for all test cases?

Henry

[Michael Krimgen]

Nitin Singla wrote:I come up with this :

@([\w-]+\.)+[\w-]*

Please correct me if I am going in wrong direction?
But I am just asking for a help.. not for any humilation for beginners in java...

thanks

The [\w-]* seems to be redundand and you miss out the .com at the end?

@([\w-]+\.)+com
would be sufficient as the + sign means at least once.

Btw, aren't you missing the www. at the beginning?

[Nitin Singla]

Hi,

@www[\.]([\w-]+\.)+com

is updated one.

Is there any suggestions?

[Aniruddh Joshi]

Are you trying to validate an email address?
Apache commons validator is pretty good for it.

[fred rosenberger]

Nitin Singla wrote:
@www[\.]([\w-]+\.)+com

Is there any suggestions?

I have two suggestions:

1) TRY IT OUT against your test cases
2) tell us if it worked or not. If it doesn't work, tell us which cases don't work, and why you think it should.

[Winston Gutkowski]

Aniruddh Joshi wrote:Are you trying to validate an email address?
Apache commons validator is pretty good for it.

Also, as was pointed out to me by Rob Spoor: javax.mail.InternetAddress.

Winston

[Winston Gutkowski]

Nitin Singla wrote:@www[\.]([\w-]+\.)+com
is updated one.
Is there any suggestions?

Yes. Stop coding.

You're suffering from "beginnersitis" at the moment, by which I mean that you're trying to solve everything with Java code.
There is no point in simply bashing out possible regexes and asking "is this right?". The fact is, if you deal with this properly, you'll know when it's right.

You've plainly done a bit of research into regexes, so you know what they expect; so my advice:
1. TURN YOUR COMPUTER OFF.
2. Sit down with your "pseudo-pattern" of '@***.**.*****.com' and write down the exact rules for it. You have an idea what regexes expect, so do it in those terms if you want; but write it in English, not it 'regex'ese.
3. When (and only when), you've done that, turn your computer back on and test it.

I'm afraid there's no shortcut to good code. You have to understand a problem before you can solve it.

Winston