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Re: Regexp to match IP address
by integral (Hermit) on Aug 06, 2004 at 14:34 UTC
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As well writing a (large) regexp yourself, there's Regexp::Common::net which packages up a regexp for matching ipv4 addresses.
(It uses a similar regexp to dsb's and mawe's above.)
--
integral, resident of freenode's #perl
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Re: Regexp to match IP address
by mawe (Hermit) on Aug 06, 2004 at 14:28 UTC
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Hi!
I found this in the Cookbook:
m/^([01]?\d\d|2[0-4]\d|25[0-5])\.([01]?\d\d|2[0-4]\d|25[0-5])\.
([01]?\d\d|2[0-4]\d|25[0-5])\.([01]?\d\d|2[0-4]\d|25[0-5])$/;
mawe | [reply]
[d/l] |
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blimey, yeah that'll do it thanks!
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print"\n ip address " if ($s=~/((\d){1,3}\.){3}(\d){1,3}/) ;
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Re: Regexp to match IP address
by dsb (Chaplain) on Aug 06, 2004 at 14:31 UTC
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Where's japhy when you need 'em. :)
I guess it kind of depends on how concerned you are with the validity of your data. Testing for 4 1-3 digit numbers seperated by dots is easy:
m/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\$/;
If you are interested making sure IP's are valid, you could do a couple of things.
One, using the above regex, you could grab the digits and test them individually.
use strict;
my @nums;
my $IP = "127.0.0.1"
(@nums) = $IP =~ m/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
# test each for <= 255 here.
# also make sure its not 0.0.0.0
Or you could use a more complicated regex to test for validity during the pattern matching. From O'Reilly's Mastering Regular Expressions:
m/^([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])\.
([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])$/;
UPDATE: I just realized this was my 150th post. Yay for me. :)
dsb
This @ISA my cool %SIG
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[d/l]
[select] |
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Hi below code validates the IP adress. Please do let me know how this can be enhanced so that it is more readable.
The validations considered are listed below.
1) If the length of any part of the IP adress seperated by the decimal is more than one digit, then it should not start with zero.
2) The first part of the IP adress seperated by the decimal cannot be zero.
3) Any part of the IP adress seperated by the decimal cannot be more than 255.
4) IP address should contain only 3 decimals.
5) The numbers cannot be negative.
print "Enter the IP address : ";
$ip = <stdin>;
if($ip =~ /^(3-9\d?|1\d?\d?|2(0-5?0-5?|6-9?))\.(0|3-9\d?|(1\d?\d?|2(0-5?0-5?|6-9?)))\.(0|3-9\d?|(1\d?\d?|2(0-5?0-5?|6-9?)))\.(0|3-9\d?|(1\d?\d?|2(0-5?0-5?|6-9?)))$/) {
print "Correct\n";
}
else {
print "Wrong\n";
}
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Re: Regexp to match IP address
by sweetblood (Prior) on Aug 06, 2004 at 14:39 UTC
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Re: Regexp to match IP address
by Ven'Tatsu (Deacon) on Aug 06, 2004 at 14:30 UTC
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You have an important error in your code, your only matching 4 digits separated by dots, I think you want /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/ That will match 4 sets of 1 to 3 digits separated by dots. | [reply]
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Re: Regexp to match IP address
by pbeckingham (Parson) on Aug 06, 2004 at 14:33 UTC
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Be aware that your code doesn't do what you think. It checks for 4 single digits separated by periods. \d checks for a single digit, not a number.
The code is too simplistic to really check for an IP address.
pbeckingham - typist, perishable vertebrate.
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Re: Regexp to match IP address
by xorl (Deacon) on Aug 06, 2004 at 14:32 UTC
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In this case if it works for you then don't bother to change.
You could try
if ($Route =~ /[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/) {
# Do stuff
}
As far as I can tell my example isn't any better | [reply]
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Re: Regexp to match IP address
by Prior Nacre V (Hermit) on Aug 06, 2004 at 19:13 UTC
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defined((grep { $_ =~ /^\d{1,3}$/ && $_ <= 255 } split /\./, $ip_addr,
+ 4)[3])
- Update
- Had 127 instead of 225 above
Regards,
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[d/l] |
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In javascript i did that:
re=/^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.([1-9]|[1-9]
+[0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}\$/;
if(re.test(document.forms[0].ipv4.value)==false){
valid=false;
message+="Wrong IP address !\n";
}
I think it's possible to match the same regexp in perl.
it seams to work...
Regards,
Orion- | [reply]
[d/l] |
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my $ip = '192.168.255.254'; # for example
# Set up the reg ex
my $ipno = qr/
2(?:5[0-5] | [0-4]\d)
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1\d\d
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[1-9]?\d
/x;
# To test
if ( $ip =~ /^($ipno(?:\.|$)){4}/ ){
print "IP OK\n";
};
I went for an interview at Arm in Cambridge, UK. They asked me to write one on the board and I wrote some lame one .. and later ... brooding on my poor attempt set out to make a better one. Driven by failure? Or maybe just really
irritated by it. I still got the job :) | [reply]
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I haven't used Javascript for 4 or 5 years. Check up-to-date documentation where appropriate.
I believe Javascript1.3 REs were the same as Perl4's. More recent JS versions may map to more recent Perl versions. However, while the latest version may provide the best solution, consider whether your intended audience will have browsers incorporating the latest JS version.
Any testing you do on the client side (e.g. Javascript in HTML) must be repeated on the server side (e.g. Perl CGI script). If you can use the same RE in both, this is possibly a good idea for consistency purposes; other considerations may override this.
I don't think your RE matches 0.n.n.n (from visual inspection). Was this intended? If not, I think you'll need: re=/^([0-9]|...
Finally, I recall running into difficulties due to differences between JavaScript, JScript and ECMAscript. Something to bear in mind if you're using advanced features.
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