Problem with a regular expression

Haazi2 · Dec 21, 2000

I'm having a problem trying to get a regular expression to
work for checking a long password. The long password consist
of an access code plus any combination of numbers, upper or
lower case letters, or the underscore(_). The total length of the long password must be at least 5 characters and cannot exceed 16 characters. The regular expression I use below doesn't seem to work. Can someone tell me what I'm doing wrong. Knowing me it's probably something simple. Thanks in advance for your help.

#!/usr/local/bin/perl -w

use strict; # enforce declarations and quoting
use diagnostics; # hints for errors

my $acode = "1234";

print "Type in your long password\n";
my $lngpswd = <STDIN>;
chomp($lngpswd);

print "\$lngpswd = $lngpswd\n";

my $result = $lngpswd =~ /^$acode\w{5,16}/ ? "OK" : "NO";
print "\$result = $result\n";

if ( $result eq "OK" )
{
print "$lngpswd is a good long password\n";
}
else
{
print "$lngpswd is an invalid Long Password!\n";
}

luciddream · Dec 21, 2000

i would use the regex to check for valid characters then make sure 16 > length($longpwd) > 5.

tanderso · Dec 21, 2000

Try encapsulating the \w since it is two characters even if supposedly interpreted as one. Also, try adding the ending marker.

/^$acode(\w){5,16}$/
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

goBoating · Dec 21, 2000

Is this what you are looking for????

Code:

#!/usr/local/bin/perl

$acode = '1234';
$lngpswd = '1234wFkti_5k482';
$lngpswd =~ /^$acode[\d|\w|_]{1,12}$/;

print &quot;M - $&amp;\n&quot;;

This assumes the access code is always four chars long. Otherwise the {1,12} will be variable instead of static.

/^$acode[\d|\w|_]{1,12}$/
$ - pins the match on the end of the string
{1,12} - find between 1 and 12 of the members of the class
[\d|\w|_] - a class of chars including digits or word chars or underscore
^ - pins the match to the start of the string

'hope this helps...

keep the rudder amid ship and beware the odd typo

tanderso · Dec 21, 2000

GB, \w already contains [a-zA-Z0-9_]. Also, the {} only works on the previous match I believe, so you would match your set 1-12. That is not what we're looking for here. I think you would have to group it to do it that way, and then you would want 1-20. Anyway, it shouldn't matter what $acode is. Just put it in front and then match (\w){5,16}.

Tell me if my changes helped.
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

Haazi2 · Dec 21, 2000

Thanks tanderso and goBoating! I got it.

I used:

$result = $lngpswd =~ /^$acode(\w){1,12}$/ ? "OK" : "NO";

Which makes sure the long password is no more than 16 characters. The $ forces the the number of characters
to match at the end of the string. The matching at the end
of the string was the key. I knew it had to be simple. Thanks again!

goBoating · Dec 22, 2000

Tom,
thanks for the critique. You're obviously correct about the \w. My code was redundant, redundant. Another moment of attention would have prevented that.

I do think the {1,12} is appropriately used, however. I intended it to apply to the char class described in [].

Thanks again.

keep the rudder amid ship and beware the odd typo

tanderso · Dec 22, 2000

Yeah, I see... I thought the part after the $acode was supposed to be 5-16 characters long, not including the $acode. I can see now that the whole thing is supposed to be that long.
Sincerely,

Tom Anderson
CEO, Order amid Chaos, Inc.

http://www.oac-design.com

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Problem with a regular expression

Haazi2

Programmer

luciddream

Programmer

tanderso

IS-IT--Management

goBoating

Programmer

tanderso

IS-IT--Management

Haazi2

Programmer

goBoating

Programmer

tanderso

IS-IT--Management

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