Although, i read about negated versions of lookahead and lookbehind
operators, i didnt really understand how to use them. Now, i get it.
Thanks John.
"John W. Krahn" <[EMAIL PROTECTED]>
12/29/2005 12:47 PM
To: Perl Beginners <beginners@perl.org>
cc:
Subject: Re: regular expression
[EMAIL PROTECTED] wrote:
> I am looking for help on a PERL regular expression that can do the
> following:
>
> 1. Make sure that the string is 20 chars or else match should fail.
> 2. The string can have word characters or spaces or comma(,),
hyphen(-),
> ampersand(&) characters.
> 3. If the string contains only spaces, then match should fail.
>
> Any ideas on how this can be done using just one regular expression ?
This may do what you want:
$ perl -le'
my @array = (
q/ /,
q/ab def,ghi-jkl&mn_pq/,
q/abcdefghi^jklmnopqrs/,
q/abcd/,
q/abcdefghijklmnopqrstuvwxyz/,
);
for ( @array ) {
print "\047$_\047 is ", /\A(?!\s{20})[\w\s,&-]{20}\z/ ? "" : "NOT ",
"valid";
}
'
' ' is NOT valid
'ab def,ghi-jkl&mn_pq' is valid
'abcdefghi^jklmnopqrs' is NOT valid
'abcd' is NOT valid
'abcdefghijklmnopqrstuvwxyz' is NOT valid
John
--
use Perl;
program
fulfillment
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