Help with Validating Email address tutorial 1

[MaxGeek]

Hi I found a lot of email validating scripts on the net, but I would like a tutorial that would teach me how to make my own custom script. Does anyone know of a good tutorial.

I only need to validate the first part of an email address in the format "john.doe"

So I want to make my own to apply specificly to this.

I just don't understand the /^(\w¦\-¦\_¦\.)+\@((\w¦\-¦\_)+\.)+[a-zA-Z]{2,}$/) part of email validating scrips so I need a tutorial that teaches you how to write that part.

Thanks,
MaxGeek

 

[uida1154]

A site I like:

http://piglet.uccs.edu/~cs301/perl/re.htm

or you simply take a book "learning perl".

 

[uida1154]

... or ask your questions on this forum

 

[duncdude]

if you want to write your own then firstly outline the checks you want to perform on the address then we'll start writing a regex to suit


Kind Regards
Duncan

 

[arcnon]

^ starts with
here you go and to really learn the power of grep in perl you need the mastering regular exrepessions book by oreilly

(\w?\-?\_?\.) a word wirh - | _ | . in it
() captures the word to $1

+ at least 1 or more \@

((\w?\-?\_)+\.)+[a-zA-Z]{2,}$/)
() outter captures everything after @ to $2
() inner captures the word up to the . in $3

(\w?\-?\_)+\.) a word wirh - | _ | . in it
+ at least 1 or more [a-zA-Z] uc lc letters
{2,} with a minimun of 2 and no max amount
$ at the end of the line

 

[arcnon]

sorry some extra crap pasted in

here you go and to really learn the power of grep in perl you need the mastering regular exrepessions book by oreilly

^ starts with
(\w\-\_\.) a word with - | _ | . in it
() captures the word to $1
+ at least 1 or more

((\w\-\_)+\.)+[a-zA-Z]{2,}$/)
() outter captures everything after @ to $2
() inner captures the word up to the . in $3

(\w\-\_)+\.) a word wirh - | _ | . in it
+ at least 1 or more
[a-zA-Z] uc lc letters
{2,} with a minimun of 2 and no max amount
$ at the end of the line

so you just have to use $1 to validate john.doe

 

[MaxGeek]

Thanks everyone for your help. I'm going to work on it now.

 

[uida1154]

Good luck and don't hesitate asking questions here. That enables me getting stars cheep

 

[MaxGeek]

Okay so I got the script working and then after playing with it I realized that my version isn't 100% fool proof.

the correct email address is "john.doe" (no need for domain)

Heres my code:
if (($email_address =~ /(\w\.)/) && (($email_address !~ /(\s)/)))

The problem is that it doesn't defend against "john." or "john.."

So my question is how do I split it at the "." and also how do i use quantifiers to limit the number of "."?

 

[uida1154]

using RE:

if ($email_address =~ /(\w+\.\w+)/)
{
 print "email address\n";
} else
{
 print "wrong\n";
}

the + means 1 or more of the previous (1 or more word characters)

 

[duncdude]

this will ensure you get only one dot

[red]\.{1}[/red]

@addresses = qw(john.doe john..doe);

foreach (@addresses) {
  if (m|\w+\.{1}\w+|) {
    print "accepted: $_\n";
  } else {
    print "rejected: $_\n";
  }
}

output:-

[blue]accepted: john.doe
rejected: john..doe[/blue]

Kind Regards
Duncan

 

[ishnid]

No need for the {1}. \. will match one dot by itself, unless you have other quantifiers after it that enable it to match more than one.