Email address regular expression

[Craig Bailey]

I've been using this pattern to verify email addresses:

^([0-9a-z]+)([0-9a-z\.-_]+)@([0-9a-z\.-_]+)\.([0-9a-z]+)

But I've recently discovered that addresses with a dash in them won't
pass this test.

Seems to me they should pass.

What's wrong?

--
Floydian Slip(tm) - "Broadcasti ng from the dark side of the moon"
Random Precision Productions(tm)
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ccb@floydiansli p.com - AIM: RandomPrec - www.floydianslip.com

[127.0.0.1]

Re: Email address regular expression

Craig Bailey wrote:
[color=blue]
> I've been using this pattern to verify email addresses:
>
> ^([0-9a-z]+)([0-9a-z\.-_]+)@([0-9a-z\.-_]+)\.([0-9a-z]+)
>
> But I've recently discovered that addresses with a dash in them won't
> pass this test.
>
> Seems to me they should pass.[/color]

[A-Z] = All characters from A to Z, maybe a \- might help ?

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[Craig Bailey]

Re: Email address regular expression

In article <Qpbgb.138702$b o1.108744@news-server.bigpond. net.au>,
"127.0.0.1" <newsgroup(at)c raznar.com@veri sign-sux-ijlkl.com> wrote:
[color=blue]
> Craig Bailey wrote:
>[color=green]
> > I've been using this pattern to verify email addresses:
> >
> > ^([0-9a-z]+)([0-9a-z\.-_]+)@([0-9a-z\.-_]+)\.([0-9a-z]+)
> >
> > But I've recently discovered that addresses with a dash in them won't
> > pass this test.
> >
> > Seems to me they should pass.[/color]
>
> [A-Z] = All characters from A to Z, maybe a \- might help ?[/color]

Aaaahhhh. But a dash doesn't need to be escaped, do it? Are you
suggesting a add a dash to the first part of the expression? Like this?

^([0-9a-z-]+)([0-9a-z\.-_]+)@([0-9a-z\.-_]+)\.([0-9a-z]+)

Of course, that would allow someone to start their address with a dash,
which I'm not certain is allowable in real email addresses.

--
Floydian Slip(tm) - "Broadcasti ng from the dark side of the moon"
Random Precision Productions(tm)
67 Union St. #2D, Winooski, Vt. 05404-1948 USA
Sundays, 7-8 pm - Champ 101.3 FM, Colchester; 102.1 FM, Randolph, Vt.
ccb@floydiansli p.com - AIM: RandomPrec - www.floydianslip.com

[Pedro]

Re: Email address regular expression

[ not posted to alt groups ]

Craig Bailey wrote:[color=blue]
> I've been using this pattern to verify email addresses:
>
> ^([0-9a-z]+)([0-9a-z\.-_]+)@([0-9a-z\.-_]+)\.([0-9a-z]+)
>
> But I've recently discovered that addresses with a dash in them won't
> pass this test.
>
> Seems to me they should pass.
>
> What's wrong?[/color]

Doesn't [0-9a-z\.-_] mean: 0 to 9 and a to z and dot to underscore?

try [0-9a-z\._-]


HTH

--
I have a spam filter working.
To mail me include "urkxvq" (with or without the quotes)
in the subject line, or your mail will be ruthlessly discarded.

[Manuel Lemos]

Re: Email address regular expression

Hello,

On 10/06/2003 07:16 AM, Craig Bailey wrote:[color=blue]
> I've been using this pattern to verify email addresses:
>
> ^([0-9a-z]+)([0-9a-z\.-_]+)@([0-9a-z\.-_]+)\.([0-9a-z]+)
>
> But I've recently discovered that addresses with a dash in them won't
> pass this test.
>
> Seems to me they should pass.
>
> What's wrong?[/color]

Character ranges that include - must start with that character. Take a
look here at this e-mail address validation class that comes with a
suitable regular expression besides the server based e-mail verification
methods.

http://www.phpclasses.org/emailvalidation

--

Regards,
Manuel Lemos

Free ready to use OOP components written in PHP

http://www.phpclasses.org/

[John Dunlop]

Re: Email address regular expression

Pedro wrote:
[color=blue]
> Doesn't [0-9a-z\.-_] mean: 0 to 9 and a to z and dot to underscore?[/color]

Yep. That's dot to underscore in "ASCII collating sequence". "Dot
to underscore" matches fifty characters in total, including all
uppercase letters, numbers, and a bunch of others -- but not the
hyphen!
[color=blue]
> try [0-9a-z\._-][/color]

Or even [\w.-]. ;-)

--
Jock

[John Dunlop]

Re: Email address regular expression

Craig Bailey wrote:
[color=blue]
> Aaaahhhh. But a dash doesn't need to be escaped, do it?[/color]

Not necessarily. But in its current position, yes, because it's
indicating a range. The *hyphen* may only be left unescaped "where
it cannot be interpreted as indicating a range".
[color=blue]
> Of course, that would allow someone to start their address with a dash,
> which I'm not certain is allowable in real email addresses.[/color]

I am certain it is.

See RFC 2822 for details, especially section 3.4.1.

--
Jock

[Andy Hassall]

Re: Email address regular expression

On Mon, 06 Oct 2003 11:56:14 -0300, Manuel Lemos <mlemos@acm.org > wrote:
[color=blue]
>Character ranges that include - must start with that character.[/color]

Or end with it.

--
Andy Hassall (andy@andyh.co. uk) icq(5747695) (http://www.andyh.co.uk)
Space: disk usage analysis tool (http://www.andyhsoftware.co.uk/space)

[Pedro]

Re: Email address regular expression

John Dunlop wrote:[color=blue]
> Or even [\w.-]. ;-)[/color]

that will match (in some locales) "josécuña"

ps. hope that gets out ok, in HTML I'd write it as
jos&eacute;cu&n tilde;a

--
I have a spam filter working.
To mail me include "urkxvq" (with or without the quotes)
in the subject line, or your mail will be ruthlessly discarded.

[John Dunlop]

Re: Email address regular expression

Pedro wrote:
[color=blue]
> John Dunlop wrote:
>[color=green]
> > Or even [\w.-]. ;-)[/color]
>
> that will match (in some locales) "josécuña"[/color]

Ah. Well spotted! I forgot what the intended use was, and
concentrated on the one part. Thanks.
[color=blue]
> ps. hope that gets out ok[/color]

It did.

--
Jock

[Lothar Scholz]

Re: Email address regular expression - Never use them

Craig Bailey <ccb@floydiansl ip.com> wrote in message news:<ccb-CE3EE0.06162706 102003@news.ver izon.net>...[color=blue]
> I've been using this pattern to verify email addresses:
>
> ^([0-9a-z]+)([0-9a-z\.-_]+)@([0-9a-z\.-_]+)\.([0-9a-z]+)
>
> But I've recently discovered that addresses with a dash in them won't
> pass this test.
>
> Seems to me they should pass.
>
> What's wrong?[/color]

In the book "Mastering Regular Expressions" there is an approximation
for internet email addresses, emails are to complex to be handed by
regular expressions correctly.

This regular expression is about 4800 characters long.

The best way is to not check any email addresses. Maybe assuming that
there must be a '@' is the only thing. Escpecially now where UTF can
be used in domain names, every [a-z] kind of pattern is simply wrong.

[William Maddler]

Re: Email address regular expression - Never use them

Lothar Scholz wrote:
[color=blue]
> In the book "Mastering Regular Expressions" there is an approximation
> for internet email addresses, emails are to complex to be handed by
> regular expressions correctly.[/color]

I agree...
usually what I check is to have smth before the @ and at least a word after
and that the mail address ends with a valid TLD...

--
WM